WO2021166930A1 - 多層フィルム、及びその製造方法 - Google Patents
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- WO2021166930A1 WO2021166930A1 PCT/JP2021/005829 JP2021005829W WO2021166930A1 WO 2021166930 A1 WO2021166930 A1 WO 2021166930A1 JP 2021005829 W JP2021005829 W JP 2021005829W WO 2021166930 A1 WO2021166930 A1 WO 2021166930A1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/04—Coating
- C08J7/042—Coating with two or more layers, where at least one layer of a composition contains a polymer binder
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B33/00—Layered products characterised by particular properties or particular surface features, e.g. particular surface coatings; Layered products designed for particular purposes not covered by another single class
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F214/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
- C08F214/18—Monomers containing fluorine
- C08F214/26—Tetrafluoroethene
- C08F214/262—Tetrafluoroethene with fluorinated vinyl ethers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/04—Coating
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
- C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L27/04—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing chlorine atoms
- C08L27/08—Homopolymers or copolymers of vinylidene chloride
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
- C08L33/04—Homopolymers or copolymers of esters
- C08L33/14—Homopolymers or copolymers of esters of esters containing halogen, nitrogen, sulfur, or oxygen atoms in addition to the carboxy oxygen
- C08L33/16—Homopolymers or copolymers of esters containing halogen atoms
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
- C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
- C08L79/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D127/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers
- C09D127/02—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment
- C09D127/12—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
- C09D127/18—Homopolymers or copolymers of tetrafluoroethene
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/03—Use of materials for the substrate
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2379/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen, or carbon only, not provided for in groups C08J2361/00 - C08J2377/00
- C08J2379/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
- C08J2379/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2427/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers
- C08J2427/02—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment
- C08J2427/12—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
- C08J2427/18—Homopolymers or copolymers of tetrafluoroethylene
Definitions
- the present invention relates to a multilayer film having a layer containing polyimide and a layer containing a tetrafluoroethylene-based polymer, and a method for producing the same.
- the printed wiring board used for transmitting high-frequency signals is required to have excellent transmission characteristics.
- a material having a low relative permittivity and dielectric loss tangent for the insulating layer of the printed wiring board As such a material, a multilayer film having a layer containing polyimide and a layer containing a tetrafluoroethylene-based polymer is known.
- this multilayer film When this multilayer film is used as an insulating layer of a printed wiring board, it is required to have excellent drilling workability because it forms via holes.
- Patent Document 1 describes a method for producing the multilayer film by laminating a film containing polyimide and a film containing a tetrafluoroethylene-based polymer. Further, Patent Documents 2 to 4 describe a method of forming a layer containing a tetrafluoroethylene polymer in the multilayer film by applying a dispersion liquid containing a powder of a tetrafluoroethylene polymer to a polyimide film and heating the film. Proposed.
- the present inventors have studied a method for producing a multilayer film having excellent adhesion between adjacent layers and drilling workability, with no wrinkles or extremely few wrinkles, for the purpose of expanding the usage mode of the multilayer film. bottom. According to the study by the present inventors, when the above-mentioned multilayer film was produced by laminating the films, it was not possible to produce a film having satisfactory drilling workability. On the other hand, when the multilayer film is produced from a dispersion liquid, there is a problem that the polyimide film shrinks when the tetrafluoroethylene polymer is fired and wrinkles are generated in the multilayer film.
- An object of the present invention is to provide a method for producing a multilayer film having excellent adhesion and drilling workability and having no or very few wrinkles, and providing a multilayer film. Further, in recent years, the multilayer film has been required to further improve the adhesion between layers.
- An object of the present invention is a method for producing a multilayer film in which a polyimide film is used as a base layer and a layer of a tetrafluoroethylene-based polymer is provided on the surface of the base layer, and the multilayer film has excellent adhesion between layers, and a multilayer film. Is provided.
- the present inventors have studied diligently, and in order to obtain a multilayer film having excellent adhesion and drilling workability and having no or very few wrinkles, a polyimide having a glass transition point and a heat-meltable tetrafluoroethylene system are used. It was found that it is necessary to form a layer containing a heat-meltable tetrafluoroethylene-based polymer in a predetermined temperature range using a polymer. Further, the present inventors have studied diligently, and in order to obtain a multilayer film having excellent adhesion between layers, a layer containing a predetermined tetrafluoroethylene polymer powder and a thermally decomposable polymer is formed on the surface of the polyimide film layer.
- a liquid composition containing a heat-meltable tetrafluoroethylene polymer powder is placed on the surface of a layer containing a polyimide having a glass transition point, and the polyimide is above the melting point of the tetrafluoroethylene polymer.
- the glass transition point of the above is heated at a temperature of + 40 ° C. or lower to form a layer containing the tetrafluoroethylene-based polymer, and the tetrafluoroethylene formed on the surfaces of the layer containing the polyimide and the layer containing the polyimide.
- a method for producing a multilayer film which comprises a multilayer film having a layer containing a based polymer.
- the method for producing (1) wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer containing a unit based on perfluoro (alkyl vinyl ether).
- the tetrafluoroethylene-based polymer contains 2.0 to 5.0 mol% of a polymer having a polar functional group or a unit based on perfluoro (alkyl vinyl ether) with respect to all the units, and has a polar functional group.
- the method for producing (1) or (2) which is a non-polymer.
- (8) It has a layer containing a polyimide having a glass transition point and a layer containing a heat-meltable tetrafluoroethylene polymer formed on both sides of the layer containing the polyimide, and the glass transition point of the polyimide is the above.
- the tetrafluoroethylene-based polymer contains 2.0 to 5.0 mol% of a polymer having a polar functional group or a unit based on perfluoro (alkyl vinyl ether) with respect to all the units, and has a polar functional group.
- the multilayer film of (8) or (9) which is a non-polymer.
- (11) The multilayer film according to any one of (8) to (10), wherein the tetrafluoroethylene polymer has a melting point of 260 to 325 ° C.
- a liquid composition containing a heat-meltable tetrafluoroethylene polymer powder and a thermodegradable polymer is placed on the surface of the polyimide film layer and heated to form a layer containing the tetrafluoroethylene polymer.
- a method for producing a multilayer film, wherein a multilayer film having the polyimide film layer and a layer containing a tetrafluoroethylene-based polymer formed on the surface of the polyimide film layer is obtained.
- the tetrafluoroethylene-based polymer contains 2.0 to 5.0 mol% of a polymer having a polar functional group or a unit based on perfluoro (alkyl vinyl ether) with respect to all the units, and has a polar functional group.
- the symbols in the formula have the following meanings.
- R 11 , R 12 and R 13 whether R 11 , R 12 and R 13 are independently alkyl or aryl groups, or whether R 11 and R 12 are hydrogen atoms and R 13 is an aryl group, respectively.
- R 11 and R 12 are independent hydrogen atoms or alkyl groups and R 13 is an alkoxy group, or R 11 is a hydrogen atom or alkyl group and R 12 and R 13 jointly form an alkylene group.
- R 21 and R 22 are groups in which R 21 is an alkyl group and R 22 is a fluoroalkyl group or jointly forms an alkylene group.
- Q 3 and Q 4 are independently alkylene groups.
- R 31 is a perfluoroalkanoic group.
- R 41 and R 42 are independently perfluoroalkyl groups.
- R 51 is an alkyl group or a cycloalkyl group.
- the polyimide of the polyimide film layer is a polyimide containing an aromatic diamine having a structure in which two or more arylene groups are linked via a linking group, or a unit based on an aliphatic diamine (15). )-(20).
- the polyimide of the polyimide film layer contains a unit based on the acid dianhydride of the aromatic tetracarboxylic dian, and the acid dianhydride of the aromatic tetracarboxylic dian has two phthalic anhydride structures as a linking group.
- a multilayer film having a polyimide film layer and a layer containing a heat-meltable tetrafluoroethylene polymer and a pyrolytic polymer on both sides of the polyimide film layer.
- the tetrafluoroethylene-based polymer contains 2.0 to 5.0 mol% of a polymer having a polar functional group or a unit based on perfluoro (alkyl vinyl ether) with respect to all the units, and has a polar functional group.
- the present invention it is possible to obtain a method for producing a multilayer film having excellent adhesion and drilling workability and having no or very few wrinkles, and a multilayer film. Further, according to the present invention, a method for producing a multilayer film having excellent adhesion between layers and a multilayer film can be obtained.
- Tg glass transition point
- DMA solid dynamic viscoelasticity
- the "heat-meltable tetrafluoroethylene polymer” means a polymer that melts without curing when measured by a differential scanning calorimetry (hereinafter, also referred to as "DSC") method.
- the "polymer melting temperature (melting point)” is the temperature corresponding to the maximum value of the polymer melting peak measured by the differential scanning calorimetry (DSC) method.
- the "imide group density of polyimide” means a value obtained by dividing the molecular weight (140.1) of the imide group portion by the molecular weight per unit.
- the molecular weight per unit is 382. It is 4, and its imide group density is 0.37 (140.1 / 382.4).
- the "water absorption rate” is defined as the mass of the test piece at the time when the test piece cut into 10 cm squares is dried at 50 ° C. for 24 hours and cooled in a desiccator, and the mass of the test piece before water immersion is used. After immersing the test piece in pure water at 23 ° C. for 24 hours, the test piece was taken out from the pure water, the water on the surface was quickly wiped off, and the mass measured within 1 minute was measured for the test piece.
- the mass after immersion in water means the rate of change in mass of the test piece before and after immersion (%) [ ⁇ (mass after immersion in water-mass before immersion in water) / mass before immersion in water ⁇ x 100].
- “Peeling strength” means that a rectangular test piece having a length of 100 mm and a width of 10 mm is cut out, and the PI layer described later and the TFE polymer layer described later are peeled from one end in the length direction of the test piece to a position 50 mm. Next, it means the maximum load when the test piece is peeled 90 degrees at a tensile speed of 50 mm / min using a tensile tester with the position 50 mm from one end in the length direction as the center.
- yield strength means a stress in which the relationship between the strain and the stress becomes non-proportional when the strain is increased, and a phenomenon in which the strain remains even if the stress is removed is started.
- stress at 5% strain when the tensile elastic modulus of the base film is measured.
- Resistant plastic deformation means a property in which the stress increases when the base film is plastically deformed, or a property in which the stress required when the base film is plastically deformed is large. It is specified by the value of "stress at 15% strain” when the tensile elastic modulus is measured.
- D50 of powder measures the particle size distribution of powder by laser diffraction / scattering method, obtains a cumulative curve with the total volume of the group of particles constituting the powder as 100%, and the cumulative volume is 50% on the cumulative curve. It is the particle size (volume-based cumulative 50% diameter) of the point.
- Powder D90 is the volume-based cumulative 90% diameter of the powder, measured in the same manner.
- D50 and D90 are values measured by dispersing powder in water using a laser diffraction / scattering type particle size distribution measuring device (LA-920 measuring device manufactured by HORIBA, Ltd.).
- the "viscosity of the liquid composition” is a value measured for the liquid composition at room temperature (25 ° C.) and at a rotation speed of 30 rpm using a B-type viscometer. The measurement is repeated 3 times, and the average value of the measured values for 3 times is used.
- the "unit” in the polymer may be an atomic group formed directly from the monomer by the polymerization reaction, and the polymer obtained by the polymerization reaction is treated by a predetermined method to convert a part of the structure. May be. Further, the unit based on the monomer A is also referred to as a monomer A unit.
- the "ten-point average roughness (Rzjis) of the surface of the metal foil” is a value specified in Annex JA of JIS B 0601: 2013.
- the production method of the present invention (hereinafter, also referred to as “this method”) is thermally meltable on the surface of a layer (hereinafter, also referred to as "PI layer") containing a polyimide (hereinafter, also referred to as "PI").
- PI layer a layer containing a polyimide (hereinafter, also referred to as "PI”).
- a liquid composition containing a powder of a tetrafluoroethylene-based polymer hereinafter, “TFE-based polymer”
- TFE-based polymer tetrafluoroethylene-based polymer
- This is a method for obtaining a multilayer film having a layer containing the formed TFE-based polymer (hereinafter, also referred to as “TFE-based polymer layer”).
- the first production method of the present invention (hereinafter, also referred to as “the present method 1") is also referred to as a PI layer (hereinafter, also referred to as "PI layer 1") containing a PI having Tg (hereinafter, also referred to as “PI1").
- a liquid composition containing a powder of the TFE polymer is placed on the surface of the TFE polymer and heated at a temperature above the melting point of the TFE polymer and at a temperature of Tg + 40 ° C. or lower of PI1 to form a layer containing the TFE polymer (hereinafter referred to as “)”.
- This is a method of forming a "TFE-based polymer layer 1" to obtain a multilayer film having a PI layer 1 and a TFE-based polymer layer 1 formed on the surface of the PI layer 1.
- a multilayer film having excellent adhesion and drilling workability and having no wrinkles or very few wrinkles can be obtained.
- the reason is not always clear, but it can be considered as follows.
- the shrinkage of the PI layer 1 due to heating promotes the densification of the PI layer 1 and improves physical properties such as water resistance, but also causes wrinkles and reduces the adhesion between layers and the drilling workability of the multilayer film. I will let you. That is, it has been difficult to produce a dense multilayer film having these physical characteristics while controlling shrinkage.
- a heat-meltable TFE-based polymer and a PI having Tg are used, and heating is performed at a temperature above the melting point of the TFE-based polymer and Tg + 40 ° C. or lower of the PI. That is, in heating, the powder of the TFE-based polymer is melted while softening the PI layer 1 to form the TFE-based polymer layer 1. Therefore, it is considered that a high degree of adhesion between the TFE polymer layer 1 and the PI layer 1 is promoted and the shrinkage is controlled. According to this method 1, it is considered that a dense multilayer film having excellent adhesion and drilling workability and having no or very few wrinkles can be obtained by such an action mechanism.
- the Tg of PI1 in this method 1 is preferably 300 ° C. or higher, more preferably 310 ° C. or higher.
- the Tg of PI1 is preferably 380 ° C. or lower, and more preferably 360 ° C. or lower. In this case, not only the softening of the PI layer 1 and the melting of the powder in heating are more likely to proceed in a balanced manner, but also the PI layer 1 and the TFE polymer layer 1 are more highly adhered to each other, and the physical characteristics of the obtained multilayer film are obtained. (High peel strength, water resistance, low line expansion, etc.) are likely to improve.
- PI1 is preferably an aromatic polyimide.
- aromatic polyimide examples include a polyimide obtained by reacting a diamine with a carboxylic acid dianhydride to synthesize a polyamic acid, and imidizing the polyamic acid by a thermal imidization method or a chemical imidization method.
- aromatic diamine is preferable.
- aromatic diamines include 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, 4,4'-oxydianiline, 3,3'-oxydianiline, and 3,4'-oxy.
- carboxylic acid dianhydride examples include pyromellitic dianhydride, 3,3'4,5'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, and the like.
- the ratio of the total number of moles of oxygen atoms derived from the ether bond contained in the diamine and the carboxylic acid dianhydride to the total number of moles of the diamine and the carboxylic acid dianhydride is preferably 35 to 70%, preferably 45 to 65. % Is more preferable.
- the flexibility of the polymer main chain of PI1 is increased, the stackability of the aromatic ring is improved, and the adhesiveness between the PI layer 1 and the TFE-based polymer layer 1 is further improved. Further, in this case, the drilling workability of the multilayer film of the present invention is also improved.
- the imide group density of PI1 is preferably 0.4 or less, and more preferably 0.3 or less.
- the imide group density of PI1 is preferably 0.1 or more. In this case, the softening of the PI layer 1 and the melting of the powder during heating are more likely to proceed in a balanced manner.
- the PI layer 1 in the present method 1 may contain an inorganic filler for the purpose of enhancing properties such as yield strength, resistance to plastic deformation, thermal conductivity, and loop stiffness.
- an inorganic filler include silicon oxide, titanium oxide, aluminum oxide, silicon nitride, boron nitride, calcium hydrogen phosphate, and calcium phosphate.
- the tensile elastic modulus of the PI layer 1 is preferably 5 GPa or more, and more preferably 10 GPa or more.
- the tensile elastic modulus is preferably 25 GPa or less, more preferably 20 GPa or less.
- the stress at 5% strain of the PI layer 1 is preferably 180 MPa or more, more preferably 210 MPa or more.
- the stress at 5% strain of the PI layer 1 is preferably 500 MPa or less.
- the stress at 15% strain of the PI layer 1 is preferably 225 MPa or more, more preferably 245 MPa or more.
- the stress at 15% strain of PI layer 1 is preferably 580 MPa or less.
- the PI layer 1 has a high yield strength and is resistant to plastic deformation, and can reduce the coefficient of linear expansion of the obtained multilayer film and more reliably prevent wrinkles from being generated therein.
- the TFE-based polymer in this method preferably further contains a unit (PAVE unit) based on perfluoro (alkyl vinyl ether) (PAVE).
- PAVE unit perfluoro (alkyl vinyl ether)
- the melting point of the TFE polymer is preferably 260 to 325 ° C, more preferably 280 to 320 ° C. In this case, not only the softening of the PI layer 1 and the melting of the powder in heating are more balanced and easily proceeded, but also the PI layer 1 and the TFE polymer layer 1 are more closely adhered to obtain the physical characteristics of the obtained multilayer film. Easy to improve.
- the Tg of the TFE polymer is preferably 75 to 125 ° C, more preferably 80 to 100 ° C.
- the TFE polymer preferably has a polar functional group.
- the polar functional group may be contained in a unit in the TFE-based polymer, or may be contained in the terminal group of the main chain of the polymer.
- the polar functional group is preferably a hydroxyl group-containing group or a carbonyl group-containing group, and a carbonyl group-containing group is particularly preferable from the viewpoint of enhancing the state stability of the liquid composition.
- the hydroxyl group-containing group is preferably a group containing an alcoholic hydroxyl group, and preferably -CF 2 CH 2 OH or -C (CF 3 ) 2 OH.
- the carbonyl group-containing group is a group containing a carbonyl group (> C (O)), and is a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC (O) NH 2 ), and an acid anhydride residue.
- a group (-C (O) OC (O)-), an imide residue (-C (O) NHC (O)-etc.) or a carbonate group (-OC (O) O-) is preferred.
- the number of carbonyl group-containing groups in the TFE-based polymer is preferably 10 to 5000, more preferably 50 to 4000, per 1 ⁇ 10 6 carbon atoms in the main chain. More preferably, 100 to 2000 pieces. In this case, the TFE-based polymer easily interacts with the PI layer 1, and the peel strength of the obtained multilayer film tends to be improved.
- the number of carbonyl group-containing groups in the TFE-based polymer can be quantified by the composition of the polymer or the method described in International Publication No. 2020/145133.
- the TFE-based polymer has a melting point of 260 to 320 ° C., contains PAVE units, and preferably contains 1.0 to 5.0 mol% of PAVE units with respect to all units, and contains TFE units and PAVE units. 2.
- a TFE-based polymer (2) containing 0 to 5.0 mol% and having no polar functional group is more preferable, and a TFE-based polymer (1) is particularly preferable from the viewpoint of adhesion and water resistance.
- the TFE-based polymer (1) preferably contains a TFE unit, a PAVE unit, and a unit based on a monomer having a polar functional group.
- the TFE-based polymer (1) or (2) not only is the powder excellent in liquid dispersibility, but also in the formation of the TFE-based polymer layer 1, it is easy to form microspherulites, and the adhesion with the PI layer 1 is good. It is easier to improve.
- the TFE-based polymer (1) has 94 to 98.99 mol% of TFE units, 1.0 to 5.0 mol% of PAVE units, and 0. It is preferable to contain 01 to 3.0 mol%, respectively.
- the monomer having a polar functional group is preferably itaconic anhydride, citraconic anhydride or 5-norbornene-2,3-dicarboxylic acid anhydride (also known as hymic anhydride; hereinafter also referred to as “NAH”).
- Specific examples of the TFE-based polymer (1) include the polymers described in International Publication No. 2018/16644.
- the TFE-based polymer (2) consists 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. Is preferable.
- the content of PAVE units in the TFE polymer (2) is preferably 2.1 mol% or more, more preferably 2.2 mol% or more, based on all the units.
- the fact that the TFE polymer (2) does not have polar functional groups means that the number of polar functional groups contained in the polymer is less than 500 per 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, and particularly preferably less than 50.
- the TFE-based 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 a terminal group of the polymer chain, and is an F polymer having a polar functional group (polymerization initiator).
- An F polymer or the like having a polar functional group derived from the above in 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 content of the TFE polymer in the powder of the TFE polymer is preferably 80% by mass or more, more preferably 100% by mass.
- the D50 of the powder is preferably 10 ⁇ m or less, more preferably 6 ⁇ m or less, still more preferably 4 ⁇ m or less.
- the D50 of the powder is preferably 0.01 ⁇ m or more, more preferably 0.1 ⁇ m or more, and even more preferably 1 ⁇ m or more.
- the powder D90 is preferably 10 ⁇ m or less.
- the powder of the TFE-based polymer may contain an inorganic substance or a polymer different from the TFE-based polymer.
- inorganic substances are oxides, nitrides, simple metals, alloys and carbons, and metal oxidation of silicon oxide (silica), beryllium oxide, cerium oxide, alumina, soda alumina, magnesium oxide, zinc oxide, titanium oxide and the like. Materials, boron nitride, steanite and magnesium metasilicate are more preferred, silica and boron nitride are even more preferred, and silica is particularly preferred. Examples of different polymers include aromatic polymers.
- aromatic polymer examples include aromatic elastomers such as styrene elastomers, aromatic polyimides, aromatic maleimides, and aromatic polyamic acids.
- a powder of a TFE-based polymer containing an inorganic substance or a different polymer has a core-shell structure having a TFE-based polymer as a core and the above component in a shell, or a TFE-based polymer having a shell and a core-shell structure having the above component in the core. Is preferable.
- the powder having such a core-shell structure is obtained, for example, by coalescing particles of a TFE-based polymer and particles of the above components by collision or agglomeration.
- the liquid composition in this method 1 is a dispersion liquid in which powder of a TFE polymer is dispersed.
- the liquid composition preferably contains a liquid dispersion medium.
- the liquid dispersion medium is a dispersion medium for the powder, which is liquid at 25 ° C.
- As the liquid dispersion medium one type may be used alone, or two or more types may be used in combination.
- the boiling point of the liquid dispersion medium is preferably 125 to 250 ° C. In this range, when the liquid dispersion medium is volatilized from the liquid composition, the powder is highly fluidized and densely packed, and as a result, a dense TFE-based polymer layer is likely to be formed.
- the liquid dispersion medium is preferably an aprotic polar medium.
- liquid dispersion medium examples include water, 1-propanol, 2-propanol, 1-butanol, 1-methoxy-2-propanol, N, N-dimethylformamide, N, N-dimethylacetamide, methyl ethyl ketone, N-methyl.
- NMP -2-pyrrolidone
- ⁇ -butyrolactone cyclohexanone
- cyclopentanone dimethyl sulfoxide
- diethyl ether diethyl ether
- dioxane butyl acetate
- methylisopropylketone cyclopentanone
- cyclohexanone ethylene glycol monoisopropyl
- ether and cellosolve methylcellosolve, ethyl cellosolve, etc.
- esters, ketones and amides are preferable from the viewpoint of adjusting the liquid physical characteristics (viscosity, thixo ratio, etc.) of the liquid composition and the high degree of interaction of each component, and ⁇ -butyrolactone, methyl ethyl ketone, cyclohexanone, N. , N-Dimethylformamide and NMP are more preferred.
- the content of the TFE polymer in the liquid composition is preferably 10% by mass or more, more preferably 25% by mass or more.
- the content of the TFE polymer is preferably 50% by mass or less, more preferably 40% by mass or less.
- the liquid composition preferably further contains an aromatic polymer (hereinafter, also referred to as "AR polymer").
- AR polymer an aromatic polymer
- the occurrence of warpage and peeling of the TFE-based polymer layer 1 is sufficiently suppressed, and the adhesiveness of the obtained multilayer film to other substrates is also improved.
- This factor is due not only that the AR polymer is highly dispersed in the TFE polymer layer 1 to alleviate the linear expansion of the TFE polymer layer 1, but also the aroma of the AR polymer present on the surface layer of the TFE polymer layer 1. It is considered that the family ring causes an interaction with PI layer 1.
- the PI layer 1 of the TFE polymer layer 1 is stacked. It is considered that the adhesion to the material is improved.
- the AR polymer aromatic polyimide and aromatic bismaleimide are preferable.
- the 5% mass reduction temperature of the AR polymer is preferably 260 to 600 ° C.
- the interface roughness of the TFE polymer layer 1 due to the decomposition gas (air bubbles) of the AR polymer or the gas (air bubbles) caused by the by-products accompanying the reaction of the AR polymer itself can be effectively suppressed, and the TFE polymer layer 1 can be effectively suppressed.
- the adhesiveness to the PI layer 1 is more likely to be improved.
- the AR-based polymer may be thermoplastic or thermosetting. If the AR-based polymer is thermoplastic, the plasticity further improves the dispersibility of the AR-based polymer in the TFE-based polymer layer 1, and the dense and uniform TFE-based polymer layer 1 is likely to be formed. As a result, the adhesion of the TFE-based polymer layer 1 to the PI layer 1 and the physical characteristics (UV absorption, etc.) of the multilayer film are likely to be improved.
- thermoplastic AR polymer thermoplastic polyimide is preferable.
- the thermoplastic polyimide means a polyimide that has been imidized and does not undergo a further imidization reaction.
- the Tg of the thermoplastic AR polymer is preferably 200 to 500 ° C.
- the AR-based polymer is thermosetting, in other words, if it is a cured product of a thermosetting aromatic polymer, the linear expansion property of the TFE-based polymer layer 1 is further reduced, and the multilayer film is warped. Easy to be suppressed.
- a thermosetting aromatic bismaleimide resin is preferable.
- AR-based polymers include aromatic polyamide-imides such as the "HPC” series (manufactured by Hitachi Kasei), “Neoprim” series (manufactured by Mitsubishi Gas Chemical Company), “Spixeria” series (manufactured by Somar), and “"Q-PILON” series (manufactured by PI Technology Research Institute), “WINGO” series (manufactured by Wingo Technology Co., Ltd.), “Toimide” series (manufactured by T & K TOKA), “KPI-MX” series (manufactured by Kawamura Sangyo Co., Ltd.), " Examples include aromatic polyimides such as the "Yupia-AT” series (manufactured by Ube Industries, Ltd.).
- the Tg of the AR polymer is equal to or lower than the melting temperature of the TFE polymer, the melting temperature of the TFE polymer is 280 to 325 ° C, and the Tg of the AR polymer is 180 to 320. It is preferably ° C.
- the TFE polymer and the AR polymer are uniformly dispersed in the TFE polymer layer 1 to improve the physical characteristics of the multilayer film, but also the TFE polymer and the AR polymer are separated from each other in a high temperature environment. It interacts with a high degree and tends to improve the heat resistance of the film.
- the liquid composition preferably further contains a surfactant from the viewpoint of promoting the dispersion of the powder and the interaction with the AR-based polymer and improving the physical properties of the formed TFE-based polymer layer 1.
- the surfactant is a component (compound) different from that of the TFE polymer and the AR polymer.
- the surfactant is preferably nonionic.
- the hydrophilic moiety of the surfactant is preferably a molecular chain containing a nonionic functional group (alcoholic hydroxyl group, oxyalkylene group, etc.).
- the hydrophobic moiety of the surfactant is preferably a molecular chain containing an alkyl group, an acetylene group, a siloxane group or a fluorine-containing group, and particularly preferably a molecular chain containing a siloxane group.
- an acetylene-based surfactant, a silicone-based surfactant and a fluorine-based surfactant are preferable, and a silicone-based surfactant is more preferable.
- the surfactant include a copolymer of a (meth) acrylate having a perfluoroalkyl group or a perfluoroalkenyl group and a (meth) acrylate having an oxyalkylene group or an alcoholic hydroxyl group.
- Specific examples of such surfactants include "Futergent” series (manufactured by Neos), “Surflon” series (manufactured by AGC Seimi Chemical), “Megafuck” series (manufactured by DIC), and "Unidyne” series (Daikin).
- the liquid composition may further contain other materials as long as the effects of the present invention are not impaired.
- Other such materials include thixo-imparting agents, defoaming agents, inorganic fillers, reactive alkoxysilanes, dehydrating agents, plasticizers, weather resistant agents, antioxidants, heat stabilizers, lubricants, antistatic agents, whitening agents. , Colorants, conductive agents, mold release agents, surface treatment agents, viscosity modifiers, flame retardants. These other materials may or may not dissolve in the liquid composition.
- the liquid composition may be applied to the surface of the PI layer 1.
- the liquid composition can be applied by spray method, roll coating method, spin coating method, gravure coating method, micro gravure coating method, gravure offset method, knife coating method, kiss coating method, bar coating method, die coating method, fountain Mayer bar. The method and the slot die coat method can be mentioned.
- the layer 1 containing the TFE polymer is formed by heating at a temperature above the melting point of the TFE polymer and at a temperature of Tg + 40 ° C. or lower of the PI1.
- the PI layer 1 is heated, it is preferable to hold it in a lower temperature region in advance to form a dry film.
- the liquid composition contains a liquid dispersion medium, it is preferable to hold it in a lower temperature region in advance and distill off (that is, dry) the liquid dispersion medium to form a dry film.
- the temperature in the low temperature region is preferably 80 to 200 ° C.
- the temperature in the low temperature region means the temperature of the atmosphere in drying.
- the holding in the low temperature region may be carried out in one step, or may be carried out in two or more steps at different temperatures.
- the dry film is further heated at a temperature above the melting point of the TFE polymer and Tg + 40 ° C. or lower of PI1 (preferably Tg + 30 ° C. or lower of PI1) to obtain the TFE polymer. Is preferably fired to form the TFE-based polymer layer 1 on the surface of the PI layer 1.
- the temperature holding time at this time is preferably 30 seconds to 5 minutes, more preferably 1 to 2 minutes.
- the atmosphere at this time may be either under normal pressure or under reduced pressure.
- the atmosphere may be any of an oxidizing gas (oxygen gas and the like) atmosphere, a reducing gas (hydrogen gas and the like) atmosphere, and an inert gas (noble gas, nitrogen gas) atmosphere.
- the PI layer 1 and the TFE polymer layer 1 are in direct contact with each other. That is, it is preferable that the TFE-based polymer layer 1 is directly formed (laminated) on the surface of the PI layer 1 without subjecting the surface treatment with a silane coupling agent, an adhesive or the like. In this case, the physical characteristics of the multilayer film are unlikely to deteriorate.
- the multilayer film obtained by the present method 1 has a high adhesion between the PI layer 1 and the TFE polymer layer 1 even if the PI layer 1 and the TFE polymer layer 1 are in direct contact with each other due to the above configuration. Sex is expressed.
- the thickness (total thickness) of the multilayer film obtained by this method 1 is preferably 25 ⁇ m or more, more preferably 50 ⁇ m or more.
- the thickness is preferably 1000 ⁇ m or less.
- the ratio of the thickness of the TFE-based polymer layer 1 to the thickness of the PI layer 1 is preferably 0.4 or more, and more preferably 1 or more, from the viewpoint of water resistance and electrical properties of the obtained film.
- the upper limit is preferably 5 or less. According to the present method 1, the adhesion between layers is enhanced by the above-mentioned action mechanism, so that a multilayer film having a high ratio and a thick TFE-based polymer layer 1 can be easily obtained.
- the thickness of the PI layer 1 is preferably 100 ⁇ m or less, more preferably 75 ⁇ m or less.
- the lower limit is preferably 10 ⁇ m or more.
- the thickness of the TFE-based polymer layer 1 is preferably 100 ⁇ m or less, more preferably 75 ⁇ m or less.
- the lower limit is preferably 10 ⁇ m or more.
- the ratio of the total thickness of the two TFE-based polymer layers 1 to the thickness of the PI layer 1 is preferably 1 or more.
- the above ratio is preferably 3 or less.
- the physical properties of PI1 in the PI layer 1 high yield strength, resistance to plastic deformation, etc.
- the TFE-based polymer in the TFE-based polymer layer 1 electric properties such as low dielectric constant and low dielectric loss tangent, low water absorption, etc.
- the first multilayer film of the present invention (hereinafter, also referred to as “the present film 1”) has a PI layer (PI layer 1) containing PI (PI1) having Tg and a TFE polymer on both sides of the PI layer 1. It has a layer containing (TFE-based polymer layer 1), and the Tg of PI1 is above the melting point of the TFE-based polymer and is not more than the melting point of the TFE-based polymer + 60 ° C.
- the range of the TFE polymer and PI1 in the film 1 is the same as that in the method 1 including the suitable range.
- the glass transition point of PI1 in the present film 1 is preferably the melting point of the TFE polymer + 10 ° C. or higher.
- the glass transition point of PI1 is preferably the melting point of the TFE polymer + 50 ° C. or lower, more preferably + 40 ° C. or lower.
- the TFE-based polymer layer 1 in the film 1 preferably further contains an aromatic polymer. Examples of the aromatic polymer include the same aromatic polymers as those in the first method.
- the peel strength of the film 1 is preferably 10 N / cm or more, more preferably 15 N / cm or more, and even more preferably 20 N / cm or more. In this case, the film 1 can be suitably used as a printed circuit board material and a coating material for metal conductors (coating material for electric wires and the like).
- the upper limit of the peel strength of the film 1 is 100 N / cm.
- the film 1 exhibits low water absorption (high water barrier property). This factor is because the low water absorption of the TFE polymer complements the high water absorption of PI1 because the TFE polymer layer 1 and the PI layer 1 are not integrated with each other and exist independently of each other. it is conceivable that.
- the water absorption rate of the film 1 is preferably 0.3% or less, more preferably 0.1% or less. In this case, the present film 1 is more difficult for water vapor to permeate and exhibits excellent insulating properties for a long period of time, and therefore can be particularly suitably used as a coating material for metal conductors.
- the lower limit of the water absorption rate of this film 1 is 0%.
- the film 1 is preferably produced by the method 1.
- a suitable range such as the thickness of the film 1 is the same as that of the multilayer film obtained by the method 1. It is preferable that the film 1 has TFE-based polymer layers 1 on both sides of the PI layer 1 from the viewpoint of being used for high-end electronic members (printed circuit board material, electric wire coating material, etc.). Since the film 1 has excellent adhesiveness on the surface of the TFE polymer layer 1, it can be easily and firmly bonded to other base materials. Examples of other base materials include metal foils and metal conductors.
- the film 1 may be formed into a metal-clad laminate by attaching a metal foil to the TFE-based polymer layers 1 on both sides.
- a metal-clad laminate can be easily processed into a printed circuit board by processing a metal foil.
- the metal constituting the metal foil include copper, copper alloy, stainless steel, nickel, nickel alloy (including 42 alloy), aluminum, aluminum alloy, titanium, and titanium alloy.
- a copper foil is preferable, a rolled copper foil having no distinction between the front and back surfaces or an electrolytic copper foil having a distinction between the front and back surfaces is more preferable, and a rolled copper foil is further preferable.
- the rolled copper foil has a small surface roughness, transmission loss can be reduced even when a metal-clad laminate is processed into a printed wiring board. Further, the rolled copper foil is preferably used after being immersed in a hydrocarbon-based organic solvent to remove rolling oil.
- the ten-point average roughness of the surface of the metal foil is preferably 0.01 to 4 ⁇ m. In this case, the adhesiveness with the TFE-based polymer layer 1 becomes good, and it is easy to obtain a printed circuit board having excellent transmission characteristics.
- the surface of the metal foil may be roughened. Examples of the roughening treatment method include a method of forming a roughening treatment layer, a dry etching method, and a wet etching method.
- the thickness of the metal foil may be a thickness that can exhibit sufficient functions in the application of the metal-clad laminate. The thickness of the metal foil is preferably less than 20 ⁇ m, more preferably 2 to 15 ⁇ m. Further, the surface of the metal foil may be partially or wholly treated with a silane coupling agent.
- Examples of the method of laminating the metal foil on the surface of the TFE-based polymer layer 1 when producing the metal-clad laminate include a method of hot-pressing the film 1 and the metal foil.
- the press temperature in the hot press is preferably 310 to 400 ° C.
- the hot press is preferably performed at a vacuum degree of 20 kPa or less from the viewpoint of suppressing air bubble mixing and suppressing deterioration due to oxidation. Further, at the time of hot pressing, it is preferable to raise the temperature after reaching the above vacuum degree. If the temperature is raised before reaching the degree of vacuum, the TFE polymer layer 1 may be crimped in a softened state, that is, in a state of having a certain degree of fluidity and adhesion, which may cause air bubbles.
- the pressure in the hot press is preferably 0.2 to 10 MPa from the viewpoint of firmly adhering the TFE-based polymer layer 1 and the metal foil while suppressing damage to the metal foil.
- the metal-clad laminate obtained by the above procedure can be used as a flexible copper-clad laminate or a rigid copper-clad laminate for manufacturing a printed circuit board.
- an interlayer insulating film may be formed on the pattern circuit, and a conductor circuit may be further formed on the interlayer insulating film.
- the interlayer insulating film may be formed by the above liquid composition.
- a solder resist may be laminated on the pattern circuit.
- the solder resist may be formed by the above liquid composition.
- a coverlay film may be laminated on the pattern circuit.
- a coated metal conductor By coating the metal conductor with the present film 1, a coated metal conductor can be obtained.
- Such coated metal conductors can be suitably used for, for example, aerospace electric wires and electric wire coils.
- As the constituent material of the metal conductor copper, a copper alloy, aluminum, and an aluminum alloy are preferable. This is because these metals have excellent conductivity.
- the cross-sectional shape of the metal conductor may be circular or rectangular.
- a coated metal conductor can be manufactured by arranging a metal conductor on one surface of the film 1 and coating the metal conductor with the film 1. Examples of the method for producing such a coated metal conductor include a method in which the film 1 is cut into a narrow strip to produce a tape, and the tape is spirally wound around the metal conductor to produce the tape. Further, after the tape is wound around the metal conductor, the tape may be further layered around the tape and wound around the metal conductor. The tape may be wrapped around a metal conductor using a wrapping machine or the like.
- a TFE polymer powder and thermodegradability are formed on the surface of the polyimide film layer (hereinafter, also referred to as "PI layer 2").
- a liquid composition containing a polymer is placed and heated to form a layer containing a TFE-based polymer (hereinafter, also referred to as "TFE-based polymer layer 2”), which is formed on the surfaces of the PI layer 2 and the PI layer 2.
- TFE-based polymer layer 2 This is a method for producing a multilayer film having the TFE-based polymer layer 2 formed therein.
- the reason why the multilayer film with improved adhesion can be obtained by this method 2 is not necessarily clear, but it is considered as follows.
- a liquid composition containing powder is applied to the surface of the PI layer 2 and heated to form the TFE polymer layer 2
- the polyimide contained in the PI layer 2 is not a little modified by the heat history, so PI Layer 2 inevitably deforms (shrinks).
- the present inventors considered that the deformation of the PI layer 2 reduces the adhesion between the two layers.
- a liquid composition containing a thermally decomposable polymer is placed on the surface of the PI layer 2 in addition to the powder, and heated to form the TFE polymer layer 2.
- the pyrolytic polymer promotes the dispersion of the powder in the liquid composition and improves its uniform dispersibility. Therefore, when the liquid composition is placed on the surface of the PI layer 2 and heated, the powder is densely packed, the powder is melt-fired, and a highly homogeneous TFE-based polymer layer 2 is formed. Adhesion is improved.
- the thermally decomposable polymer segregated at the interface relaxes the deformation of the PI layer 2 as a plastic component, a soft component, or an adhesive component, and improves the adhesion between the two layers. This method 2 will be further described.
- the imide group density of PI in the PI layer 2 in this method 2 is preferably 0.35 or less, more preferably 0.3 or less.
- the imide group density of PI is preferably 0.1 or more. In this case, the deformation of the PI layer 2 and the melting of the powder during heating proceed in a balanced manner, and the TFE-based polymer layer 2 and the PI layer 2 tend to have excellent adhesion.
- the PI of the PI layer 2 preferably contains a unit based on an aromatic diamine having a structure in which two or more arylene groups are linked via a linking group.
- aromatic diamine include the same aromatic diamines as in the first method.
- the PI of the PI layer 2 preferably contains a unit based on an aliphatic diamine. Examples of aliphatic diamines include 1,2-ethylenediamine, 1,3-propylene diamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, and 1,8.
- Examples thereof include -octanediamine, 2-methyl-1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine.
- One type of diamine may be used alone, or two or more types may be used in combination.
- the PI of the PI layer 2 contained a unit based on the acid dianhydride of the aromatic tetracarboxylic dian, in which the acid dianhydride of the aromatic tetracarboxylic dianhydride was linked with two phthalic anhydride structures via a linking group. It preferably has a structure.
- the PI of the PI layer 2 preferably has Tg.
- the preferred embodiment of the PI in the present method 2 is the same as that of the PI 1 in the present method 1. In this case, it is easy to obtain a multilayer film which is excellent in adhesion between adjacent layers and drilling workability and has no wrinkles or very few wrinkles.
- the definition and scope of the TFE polymer in this method 2 are as described above.
- the thermally decomposable polymer in this method 2 is thermally decomposed by heating, the thermally decomposed product derived from the thermally decomposable polymer is generated at the interface between the TFE polymer layer 2 and the PI layer 2 as the TFE polymer layer 2 is formed. Segregate into. Then, it is considered that the pyrolyzed product derived from the thermally decomposable polymer segregated at the interface further alleviates the deformation of the PI layer 2 as a plastic component, a soft component, or an adhesive component, and further improves the adhesion between the two layers. .. Therefore, in the multilayer film obtained by the present method 2, the TFE-based polymer layer 2 may contain a pyrolyzed product derived from a thermally decomposable polymer.
- the thermally decomposable polymer is preferably a thermally decomposable (meth) acrylic polymer.
- the thermally decomposable (meth) acrylic polymer preferably has a fluoroalkyl group or a fluoroalkenyl group in the side chain.
- the fluoroalkyl group or fluoroalkenyl group preferably has 4 to 16 carbon atoms. Further, an ether oxygen atom may be inserted between the carbon atoms of the fluoroalkyl group or the fluoroalkenyl group.
- CH 2 C (CH 3 ) C (O) OCH 2 CH 2 (CF 2 ) 6 F
- the thermally decomposable (meth) acrylic polymer preferably has a hydroxyl group or an oxyalkylene group in the side chain.
- the oxyalkylene group may be composed of one kind of oxyalkylene group or may be composed of two or more kinds of oxyalkylene groups. In the latter case, different types of oxyalkylene groups may be arranged in a random manner or in a block shape.
- As the oxyalkylene group an oxyethylene group or an oxypropylene group is preferable, and an oxyethylene group is particularly preferable.
- the thermally decomposable (meth) acrylic polymer preferably has a fluoroalkyl group or a fluoroalkenyl group and a hydroxyl group or an oxyalkylene group, respectively.
- Specific examples of such a thermally decomposable (meth) acrylic polymer include a copolymer of a (meth) acrylate having a fluoroalkyl group or a fluoroalkenyl group and a (meth) acrylate having a hydroxyl group or an oxyalkylene group. Be done.
- An example of a pyrolyzed product derived from a thermally decomposable (meth) acrylic polymer is a compound having a carboxyl group, a hydroxyl group, and a polyoxyalkylene group.
- the pyrolyzed product is, for example, a (meth) acrylic polymer having a hydroxyl group and a polyoxyalkylene group when the pyrolyzable polymer is a (meth) acrylic polymer having a polyoxyalkylene group. If you get it.
- the (meth) acrylic polymer is thermally decomposed, and the compounds having these hydrophilic groups segregate at the interface, so that the adhesion between the TFE polymer layer 2 and the PI layer 2 is improved.
- a metal foil such as a copper foil is attached to the surface of the TFE polymer layer 2, and the compound having these hydrophilic groups is the TFE polymer layer 2.
- the adhesiveness with the metal foil is improved.
- the thermally decomposable (meth) acrylic polymer preferably has any one group represented by the following formulas (1) to (5) in the side chain.
- the thermal decomposability of the (meth) acrylic polymer is likely to be improved, and the decomposed product further alleviates the deformation generated in the PI layer 2 as a plastic component, a soft component, or an adhesive component, and improves interlayer adhesion. It is easier to improve.
- Equations (1) -C (O) -OC (-R 11 ) ( -R 12 ) (-R 13 ) Equation (2) -C (O) -OCH (-R 21 ) (-OR 22 ) Equation (3) -C (O) -O-Q 3- O-CF (CF 3 ) (-R 31 ) Equation (4) -C (O) -OQ 4- OC (CF 3 ) ( C (-R 41 ) ( -R 42 )) Equation (5) -C (O) -OC (CF 3 ) 2 (-R 51 )
- the symbols in the formula have the following meanings.
- R 11 , R 12 and R 13 whether R 11 , R 12 and R 13 are independently alkyl or aryl groups, or whether R 11 and R 12 are hydrogen atoms and R 13 is an aryl group, respectively.
- R 11 and R 12 are independent hydrogen atoms or alkyl groups and R 13 is an alkoxy group, or R 11 is a hydrogen atom or alkyl group and R 12 and R 13 jointly form an alkylene group.
- R 21 and R 22 are groups in which R 21 is an alkyl group and R 22 is a fluoroalkyl group or jointly forms an alkylene group.
- Q 3 and Q 4 are independently alkylene groups.
- R 31 is a perfluoroalkanoic group.
- R 41 and R 42 are independently perfluoroalkyl groups.
- R 51 is an alkyl group or a cycloalkyl group.
- X 11 represents a hydrogen atom, a chlorine atom or a methyl group.
- X 12 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
- Q 5 indicates an alkylene group or an oxyalkylene group.
- R 61 represents a perfluoroalkyl group or a perfluoroalkenyl group.
- R 11 , R 12 and R 13 are as described above. It is preferable that X 11 and X 12 are independently hydrogen atoms or methyl groups, respectively.
- the number of carbon atoms of the carbon-containing group in Q 5 and R 61 are each independently, is preferably 1 to 16.
- Q 5 is, -CH 2 CH 2 -, - CH 2 CH 2 CH 2 CH 2 -, - CH 2 CH 2 O- or -CH 2 CH 2 CH 2 CH 2 is preferably O-.
- the monomer represented by the formula (1) include the following monomers. As such a monomer, one kind may be used alone, or two or more kinds may be used.
- the content of such monomer-based units with respect to all the units contained in the (meth) acrylic polymer having a group represented by the formula (1) is preferably 20 to 80 mol%.
- the fluorine content of the thermally decomposable polymer having a group represented by the formula (1) is preferably 10 to 45% by mass, particularly preferably 15 to 40% by mass.
- the pyrolytic polymer having a group represented by the formula (1) is preferably nonionic.
- the mass average molecular weight of the thermally decomposable polymer having a group represented by the formula (1) is preferably 2000 to 80,000, and particularly preferably 6000 to 20000.
- R 22 is a fluoroalkyl group, preferably a fluoroalkyl group having 1 to 6 carbon atoms to which a fluorine atom is directly bonded, more preferably a fluoroalkyl group having 4 to 6 carbon atoms, and a fluoroalkyl group having 6 carbon atoms. Is particularly preferable.
- Q 6 is, - (CH 2) 2 - or - (CH 2) 4 - a.
- Q 7 is an alkylene group having 2 or 4 carbon atoms.
- the liquid composition in this method 2 is a dispersion liquid in which powder of a TFE polymer is dispersed.
- the liquid composition preferably contains a liquid dispersion medium.
- the definition and scope of the liquid dispersion medium in the present method 2 are the same as those of the liquid dispersion medium in the present method 1, including the preferred embodiment thereof.
- the content of the TFE polymer in the liquid composition is preferably 10% by mass or more, more preferably 25% by mass or more.
- the content of the TFE polymer is preferably 50% by mass or less, more preferably 40% by mass or less.
- the content of the thermally decomposable polymer in the liquid composition is preferably 0.1% by mass or more, more preferably 1% by mass or more.
- the content of the thermally decomposable polymer is preferably 20% by mass or less, more preferably 5% by mass or less.
- the liquid composition may optionally contain components other than the powder, the pyrolytic polymer, and the liquid dispersion medium.
- the liquid composition may contain a polyimide, a polyimide precursor or a bismaleimide, and preferably contains a polyimide or a polyimide precursor.
- the polyimide precursor is a compound that forms polyimide during heating in the formation of the TFE-based polymer layer 2, and examples thereof include polyamic acids.
- polyimide when used, it also includes a polyimide precursor.
- the liquid composition contains polyimide or bismaleimide
- the occurrence of warpage and peeling in the formed TFE-based polymer layer 2 is sufficiently suppressed, and the adhesiveness to other substrates is also improved.
- the polyimide or bismaleimide contained in the TFE-based polymer layer 2 is highly dispersed, and the linear expansion property of the TFE-based polymer layer 2 tends to be lowered.
- aromatic polyimide or aromatic bismaleimide is preferable.
- the polyimide or bismaleimide present on the surface layer of the TFE-based polymer layer 2 interacts with the PI layer 2.
- the PI layer of the TFE polymer layer 2 is stacked. It is considered that the adhesion to 2 is improved. Further, when the TFE-based polymer layer 2 contains an aromatic polyimide or an aromatic maleimide, the multilayer film obtained by the present method 2 tends to be excellent in peel strength and UV absorption (that is, UV processability).
- the polyimide may be thermoplastic or thermosetting. If the polyimide is thermoplastic, the dispersibility of the polyimide in the TFE-based polymer layer 2 is further improved by the development of the plasticity at the time of heating, and the dense and uniform TFE-based polymer layer 2 is likely to be formed. As a result, the adhesion of the TFE polymer layer 2 to the PI layer 2 is likely to be improved.
- the thermoplastic polyimide means a polyimide that has been imidized and does not undergo a further imidization reaction.
- thermosetting in other words, if it is a cured product of thermosetting polyimide, the linear expansion property of the TFE-based polymer layer 2 is further lowered, and the occurrence of warpage of the multilayer film is suppressed.
- thermosetting polyimide a polyimide having no plasticity formed by an imidization reaction of a polyimide precursor (polyamic acid or the like) is preferable.
- polyimide examples include "Neoprim” series (manufactured by Mitsubishi Gas Chemical Company), “Spixeria” series (manufactured by Somar), “Q-PILON” series (manufactured by PI Technology Research Institute), and “WINGO” series (Wingo). "Technology”), “Tomid” series (T & K TOKA), “KPI-MX” series (Kawamura Sangyo), “Yupia-AT” series (Ube Industries).
- the polyimide is preferably a polymer that is soluble in the liquid dispersion medium of the liquid composition.
- the interaction between the polyimide and other components (TFE-based polymer, liquid dispersion medium) in the liquid composition is enhanced, and the dispersibility of the liquid composition is more likely to be improved.
- the fluidity of the polyimide is increased and the polyimide is highly dispersed. Therefore, the physical properties based on the TFE-based polymer such as electrical characteristics are highly exhibited, and the TFE-based polymer layer 2 having higher adhesion to the PI layer 2 is likely to be formed.
- the solubility (g / solvent 100 g) of polyimide in a liquid dispersion medium of a liquid composition at 25 ° C. is preferably 5 to 30.
- the bismaleimide a thermosetting aromatic bismaleimide resin is preferable. In this case, the linear expansion property of the TFE-based polymer layer 2 is further reduced, and the warp of the film is likely to be suppressed.
- the liquid composition in the second method may further contain other materials as long as the effects of the present invention are not impaired. Examples of such other materials include those similar to the other materials in the present method 1.
- the liquid composition may be applied to the surface of the PI layer 2. Examples of the method for applying the liquid composition include the same method as the method for applying the liquid composition in the present method 1.
- the PI layer 2 when the PI layer 2 is heated after the liquid composition is arranged, it is preferable to maintain the temperature in the low temperature region to form a dry film.
- the liquid composition contains a liquid dispersion medium, it is preferable to hold the liquid composition in a lower temperature region in advance and distill off (that is, dry) the liquid dispersion medium to form a dry film.
- the temperature in the low temperature region is preferably 80 to 200 ° C.
- the temperature in the low temperature region means the temperature of the atmosphere in drying. Holding at a temperature in the low temperature region may be carried out in one step, or may be carried out in two or more steps at different temperatures.
- the dry film is further heated in a temperature region exceeding the holding temperature in the low temperature region (hereinafter, also referred to as “firing region”), and the TFE polymer is calcined to perform PI. It is preferable to form the TFE-based polymer layer 2 on the surface of the layer 2.
- the temperature of the firing region means the temperature of the atmosphere in firing.
- the formation of the TFE-based polymer layer 2 proceeds by densely packing the powder particles and fusing the TFE-based polymer.
- the liquid composition contains a thermoplastic polyimide
- a TFE polymer layer 2 composed of a mixture of the TFE polymer and the polyimide is formed, and the liquid composition is a thermosetting polyimide or a thermosetting maleimide.
- a TFE-based polymer layer 2 composed of a TFE-based polymer and a cured product of polyimide or a thermosetting maleimide is formed.
- the atmosphere in firing may be either under normal pressure or under reduced pressure.
- the atmosphere may be any of an oxidizing gas (oxygen gas and the like) atmosphere, a reducing gas (hydrogen gas and the like) atmosphere, and an inert gas (noble gas, nitrogen gas) atmosphere.
- the temperature of the firing region is preferably equal to or higher than the melting temperature of the TFE polymer, and particularly preferably 300 to 380 ° C.
- the time for keeping the temperature of the firing region is preferably 30 seconds to 5 minutes, and particularly preferably 1 to 2 minutes.
- a liquid composition is placed on the surface of the PI layer 2 and heated at a temperature above the melting point of the TFE polymer and at a temperature of Tg + 40 ° C. or lower of the PI to heat the TFE polymer layer. It is preferable to form 2.
- the preferred embodiment of the method for forming the TFE-based polymer layer 2 in the present method 2 is the same as that for the method for forming the TFE-based polymer layer 1 in the present method 1.
- the PI layer 2 and the TFE polymer layer 2 are in direct contact with each other.
- the preferable range of the thickness of the multilayer film and the thickness of each layer obtained by the present method 2 is the same as that of the thickness of the multilayer film and the thickness of each layer obtained by the present method 1.
- the second multilayer film of the present invention (hereinafter, also referred to as “the present film 2”) is a TFE-based film containing a heat-meltable TFE-based polymer and a pyrolytic polymer on both sides of the PI layer 2 and the PI layer 2. It has a polymer layer 2.
- the range of the TFE polymer and PI in the present film 2 is the same as that in the present method 2, including the suitable range.
- the TFE-based polymer layer 2 in the film 2 preferably contains an aromatic polymer.
- the film 2 tends to have excellent workability.
- the aromatic polymer include the same aromatic polymer as in the first method.
- the TFE-based polymer layer 2 in the film 2 preferably contains a pyrolyzed product derived from a thermally decomposable polymer. In this case, the adhesiveness between adjacent layers in the present film 2 is likely to be improved, and the present film 2 is likely to be excellent in water resistance.
- the peel strength of the film 2 is preferably 10 N / cm or more, more preferably 15 N / cm or more, and even more preferably 20 N / cm or more.
- the film 2 can be suitably used as a printed circuit board material and a coating material for metal conductors (coating material for electric wires and the like).
- the upper limit of the peel strength of the film 2 is 100 N / cm.
- the film 2 exhibits low water absorption (high water barrier property). It is considered that this factor is because the low water absorption of the TFE polymer complements the high water absorption of PI because the polymer layer 2 and the PI layer 2 are not integrated with each other and exist independently of each other. Be done.
- the water absorption rate of the film 2 is preferably 0.1% or less, more preferably 0.07% or less, still more preferably 0.05% or less. In this case, the present film 2 is more difficult for water vapor to permeate and exhibits excellent insulating properties for a long period of time, and therefore can be particularly suitably used as a coating material for metal conductors.
- the lower limit of the water absorption rate of the film 2 is 0%.
- the preferred embodiment of the configuration of the present film 2 is the same as the preferred embodiment of the configuration of the multilayer film of the present method 2. Since the multilayer film of this method 2 has excellent adhesiveness on the surface of the TFE-based polymer layer 2, it can be easily and firmly bonded to other base materials. Examples of other base materials include metal foils and metal conductors.
- the multilayer film of the present method 2 may be formed as a metal-clad laminate by attaching a metal foil to the TFE-based polymer layers 2 on both sides. Such a metal-clad laminate can be easily processed into a printed circuit board by processing a metal foil.
- TFE-based polymer 11 A polymer containing 98.0 mol%, 1.9 mol%, and 0.1 mol% of TFE units, PPVE units, and NAH units in this order (melting temperature: 300 ° C.).
- TFE-based polymer 12 Polymer containing 98.5 mol% and 1.5 mol% of TFE units and PPVE units in this order (melting temperature: 305 ° C.)
- the TFE-based polymer 11 has 1000 carbonyl group-containing groups per 1 ⁇ 10 6 main chain carbon atoms, and the TFE-based polymer 12 has 40 carbonyl group-containing groups.
- Powder 12 Powder of TFE polymer 12 (average particle size (D50): 1.5 ⁇ m)
- Thermoplastic Aromatic Polypolymer 11 3,3'4,4'-benzophenone tetracarboxylic acid dianhydride and 3,3'4,4'-biphenyltetracarboxylic acid dianhydride, 2,4-diaminotoluene and 2 , 2-Bis ⁇ 4- (4-aminophenoxy) phenyl ⁇ Block copolymer with propane ⁇ Polymer dispersant>
- thermoplastic aromatic polyimide 11 A liquid composition 11 containing 40% by mass of powder 11 and 4% by mass of (meth) acrylic polymer 11 using N-methyl-2-pyrrolidone (NMP) as a liquid dispersion medium was prepared. A varnish (solvent: NMP) of the thermoplastic aromatic polyimide 11 was added to the liquid composition 11 to further prepare a liquid composition 12 containing 0.5% by mass of the thermoplastic aromatic polyimide 11.
- NMP N-methyl-2-pyrrolidone
- Example 1-1 The liquid composition 12 was applied to one surface of the PI film 11 by a small-diameter gravure reverse method and passed through a ventilation drying furnace (furnace temperature: 150 ° C.) for 3 minutes to remove NMP and form a dry film. .. Further, the liquid composition 12 was similarly applied and dried on the other surface to form a dry film. Next, the PI film 11 having the dry film formed on both sides was passed through a far-infrared ray furnace (furnace temperature: 320 ° C.) for 5 minutes to melt-fire the powder 11.
- a ventilation drying furnace furnace temperature: 150 ° C.
- the liquid composition 12 was similarly applied and dried on the other surface to form a dry film.
- the PI film 11 having the dry film formed on both sides was passed through a far-infrared ray furnace (furnace temperature: 320 ° C.) for 5 minutes to melt-fire the powder 11.
- TFE-based polymer layer (thickness: 25 ⁇ m) containing the TFE-based polymer 11 and the thermoplastic aromatic polyimide is formed on both sides of the PI film 11, and the TFE-based polymer layer, the PI film 11, and the TFE-based polymer layer are formed.
- a multilayer film 1 directly formed in order was obtained.
- Example 1-2 A multilayer film 12 was obtained in the same manner as in Example 1-1 except that the powder 11 was changed to the powder 12.
- Example 1-3 A multilayer film 13 was obtained in the same manner as in Example 1-1 except that the PI film 11 was changed to the PI film 12.
- Example 1-4 A multilayer film 14 was obtained in the same manner as in Example 1-1 except that the liquid composition 12 was changed to the liquid composition 11.
- Example 1-5 A multilayer film 15 was obtained in the same manner as in Example 1-1 except that the melt firing temperature was changed to 300 ° C.
- Example 1-6 A multilayer film 16 was obtained in the same manner as in Example 1-1 except that the melt firing temperature was changed to 350 ° C.
- Example 1-7 A multilayer film 17 was obtained in the same manner as in Example 1-1 except that the melt firing temperature was changed to 360 ° C.
- Example 1-8 A film (thickness: 50 ⁇ m) obtained by melt extrusion molding the TFE polymer 11 is opposed to both sides of the PI film 11 and vacuum pressed at 320 ° C. for 15 minutes to obtain a TFE polymer layer and the PI film 11. , A multilayer film 18 in which a TFE-based polymer layer was directly formed in this order was obtained. [Example 1-9] A multilayer film 19 was obtained in the same manner as in Example 1-1 except that the PI film 11 was changed to the PI film 13.
- ⁇ Evaluation items >> ⁇ Appearance> The obtained multilayer film was allowed to stand on a smooth glass surface, the presence or absence of warpage (waviness) was confirmed, and the evaluation was made according to the following criteria. ⁇ : No warpage is confirmed. ⁇ : The occurrence of warpage is confirmed. ⁇ : Not only the occurrence of warpage is confirmed, but also wrinkles are formed. The multilayer film 19 had no wrinkles and had the highest surface smoothness among the multilayer films.
- Heat shrinkage rate A sample cut into 12 cm squares was prepared from the obtained multilayer film, and the heat shrinkage rate was determined by the following method. At 25 ° C., draw a straight line with a length of about 10 cm on the sample, and let the distance between the end points of the straight line be the initial length L 0 . Next, the sample is heat-treated at 320 ° C. for 5 minutes, cooled to 25 ° C., the linear distance L 1 between the end points of the straight lines drawn on the sample is measured, and the heat shrinkage rate (%) is obtained by the following formula 1. , Evaluated according to the following criteria.
- Heat shrinkage rate (%) (1-L 1 / L 0 ) ⁇ 100 ⁇ ⁇ ⁇ Equation 1 ⁇ : Heat shrinkage rate ⁇ 2% ⁇ : 2% ⁇ heat shrinkage rate ⁇ 3% ⁇ : Heat shrinkage rate ⁇ 3%
- Copper foil electrolytic copper foil CF-T49A-DS-HD2-12, Fukuda Metal Foil Powder Industry Co., Ltd.
- a double-sided copper-clad laminate was produced.
- each double-sided copper-clad laminate was irradiated with a UV-YAG laser having a wavelength of 355 nm so as to orbit around a circumference of 100 ⁇ m in diameter.
- a circular through hole was formed in the double-sided copper-clad laminate.
- the laser output was 1.2 W
- the laser focal diameter was 25 ⁇ m
- the number of orbits on the circumference was 20 times
- the oscillation frequency was 40 kHz.
- the water absorption rate was measured according to the method of JISK7209: 2000A.
- the obtained multilayer film was cut into 10 cm squares to prepare test pieces.
- the test piece was dried at 50 ° C. for 24 hours and cooled in a desiccator.
- the mass of the test piece at this point was defined as the mass of the test piece before immersion in water.
- the dried test piece was immersed in pure water at 23 ° C. for 24 hours.
- the test piece was taken out from pure water, the water on the surface was quickly wiped off, and the mass was measured within 1 minute to obtain the mass of the test piece after being immersed in water.
- the mass change rate of the test piece before and after immersion was determined as the "water absorption rate" of the multilayer film, and the water resistance was evaluated according to the following criteria.
- ⁇ The water absorption rate is 0.3% or less.
- ⁇ The water absorption rate is more than 0.3% and less than 1%.
- X The water absorption rate is 1% or more.
- TFE-based polymer 21 A polymer having a polar functional group containing 98.0 mol%, 1.9 mol%, and 0.1 mol% of TFE units, PPVE units, and NAH units in this order (melting temperature 300 ° C.).
- the TFE polymer 21 has 1000 carbonyl group-containing groups per 1 ⁇ 10 6 carbon atoms in the main chain.
- Powder 21 Powder of TFE polymer 21 (average particle size (D50): 2 ⁇ m)
- PI film 21 The acid anhydride monomer is BPDA (3,3', 4,4'-biphenyltetracarboxylic dianhydride), and the diamine monomer is BAFL (9,9-bis (4-aminophenyl) fluorene).
- Polymer (imide group density: ⁇ 0.35) film (thickness: 50 ⁇ m)
- the Tg of the PI film 21 is 320 ° C., and the tensile elastic modulus is 9.5 GPa.
- PI film 22 Polyimide (imide group density:> 0.35) film (thickness: 50 ⁇ m) in which the acid anhydride monomer is BPDA and the diamine monomer is PDA (p-phenylenediamine).
- the Tg of the PI film 22 is 315 ° C., and the tensile elastic modulus is 8.2 GPa.
- Liquid composition 21 Powder dispersion containing powder 21 (30% by mass), thermoplastic polyimide (1% by mass), (meth) acrylic polymer 21 (3% by mass) and NMP (remaining portion)
- Liquid composition 22 Powder dispersion liquid composition 23: powder 21 (30% by mass) containing powder 21 (30% by mass), thermoplastic polyimide (1% by mass), (meth) acrylic polymer 22 (3% by mass) and NMP (remaining). %), (Meta) Acrylic Polymer 21 (3% by Mass) and NMP (Remaining), Powder Dispersion Liquid Composition 24: Powder 21 (30% by Mass) and NMP (Remaining).
- Example 2-1 Production example of multilayer film 21
- the liquid composition 21 is applied to one surface of the PI film 21 by the small-diameter gravure reverse method, and dried in a ventilation drying furnace (furnace temperature: 150 ° C.) for 3 minutes.
- NMP was removed to form a dry film.
- the liquid composition 21 was similarly applied and dried on the other surface to form a dry film.
- the powder 21 was melt-fired by passing it through a far-infrared ray furnace (furnace temperature: 320 ° C.) for 20 minutes.
- a polymer layer (thickness: 25 ⁇ m) containing the TFE polymer 21 and the thermoplastic polyimide is formed on both outermost surfaces of the PI film 21, and the TFE polymer layer, the PI film layer, and the TFE polymer layer are arranged in this order.
- a multilayer film 21 having a structure was obtained.
- Example 2-2 Production example of multilayer film 22 A multilayer film 22 was obtained in the same manner as in Example 2-1 except that the PI film 21 was changed to the PI film 22.
- Example 2-3 Production example of multilayer film 23 A multilayer film 23 was obtained in the same manner as in Example 2-1 except that the liquid composition 21 was changed to the liquid composition 23.
- Example 2-4 Production example of multilayer film 24 A multilayer film 24 was obtained in the same manner as in Example 2-1 except that the liquid composition 21 was changed to the liquid composition 22.
- Example 2-5 Production example of multilayer film 25 A multilayer film 25 was obtained in the same manner as in Example 2-1 except that the liquid composition 21 was changed to the liquid composition 24.
- ⁇ Evaluation items >> ⁇ Decomposition of layer surface>
- the surface of the TFE polymer layer is analyzed by total reflection-infrared absorption spectroscopy (ATR-IR analysis method) and AFM-IR method, evaluated from the types of functional groups detected, and the former method is used.
- ATR-IR analysis method total reflection-infrared absorption spectroscopy
- AFM-IR method evaluated from the types of functional groups detected, and the former method is used.
- a multilayer film having excellent adhesion and drilling workability and having no wrinkles or very few wrinkles can be obtained. Further, according to the present invention, a multilayer film having excellent adhesion between layers can be obtained.
- the multilayer film of the present invention can be processed and used for antenna parts, printed circuit boards, aircraft parts, automobile parts, and the like. Further, the metal conductor coated with such a multilayer film exhibits high insulating properties for a long period of time, and can be suitably used for an electric wire or a conducting coil for aerospace.
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Abstract
Description
この多層フィルムをプリント配線基板の絶縁層として用いる場合、ビアホールを形成するため、穴あけ加工性が優れることが求められる。
また、特許文献2~4には、上記多層フィルムにおけるテトラフルオロエチレン系ポリマーを含む層を、ポリイミドのフィルムにテトラフルオロエチレン系ポリマーのパウダーを含む分散液を塗布し、加熱して形成する方法が提案されている。
本発明者らの検討によると、上記多層フィルムを、フィルムを貼り合わせて作製すると、満足な穴あけ加工性を有するフィルムを作製できなかった。一方、上記多層フィルムを、分散液から作製すると、テトラフルオロエチレン系ポリマーの焼成時にポリイミドフィルムが収縮し、多層フィルムに皺が発生する問題があった。
また、近年、上記多層フィルムには、層間の密着性の更なる向上が要求されている。
本発明の目的は、ポリイミドのフィルムをベース層とし、ベース層の表面にテトラフルオロエチレン系ポリマーの層を設けた多層フィルムであって、層間の密着性に優れる多層フィルムの製造方法、及び多層フィルムの提供である。
また、本発明者らは鋭意検討し、層間の密着性に優れる多層フィルムを得るには、ポリイミドフィルム層の表面に、所定のテトラフルオロエチレン系ポリマーのパウダー及び熱分解性ポリマーを含む層を形成する必要があることを知見した。
本発明は、下記の態様を有する。
(1)ガラス転移点を有するポリイミドを含む層の表面に、熱溶融性のテトラフルオロエチレン系ポリマーのパウダーを含む液状組成物を配置し、上記テトラフルオロエチレン系ポリマーの融点超、かつ、上記ポリイミドのガラス転移点+40℃以下の温度にて加熱し、上記テトラフルオロエチレン系ポリマーを含む層を形成して、上記ポリイミドを含む層と、上記ポリイミドを含む層の表面に形成された上記テトラフルオロエチレン系ポリマーを含む層とを有する多層フィルムを得る、多層フィルムの製造方法。
(2)上記テトラフルオロエチレン系ポリマーが、ペルフルオロ(アルキルビニルエーテル)に基づく単位を含むテトラフルオロエチレン系ポリマーである、(1)の製造方法。
(3)上記テトラフルオロエチレン系ポリマーが、極性官能基を有するポリマー、又は、全単位に対してペルフルオロ(アルキルビニルエーテル)に基づく単位を2.0~5.0モル%含み、極性官能基を有さないポリマーである、(1)又は(2)の製造方法。
(4)上記液状組成物が、さらに芳香族ポリマーを含む、(1)~(3)のいずれかの製造方法。
(5)上記テトラフルオロエチレン系ポリマーを含む層の厚さが、100μm以下である、(1)~(4)のいずれかの製造方法。
(6)上記ポリイミドを含む層の厚さに対する、上記テトラフルオロエチレン系ポリマーを含む層の厚さの比が、0.4以上である、(1)~(5)のいずれかの製造方法。
(7)上記ポリイミドを含む層の両面に、上記テトラフルオロエチレン系ポリマーを含む層をそれぞれ形成する、(1)~(6)のいずれかの製造方法。
(8)ガラス転移点を有するポリイミドを含む層と、上記ポリイミドを含む層の両面に形成された熱溶融性のテトラフルオロエチレン系ポリマーを含む層とを有し、上記ポリイミドのガラス転移点が上記テトラフルオロエチレン系ポリマーの融点超、かつ、上記テトラフルオロエチレン系ポリマーの融点+60℃以下である、多層フィルム。
(9)上記テトラフルオロエチレン系ポリマーが、ペルフルオロ(アルキルビニルエーテル)に基づく単位を含むテトラフルオロエチレン系ポリマーである、(8)の多層フィルム。
(10)上記テトラフルオロエチレン系ポリマーが、極性官能基を有するポリマー、又は、全単位に対してペルフルオロ(アルキルビニルエーテル)に基づく単位を2.0~5.0モル%含み、極性官能基を有さないポリマーである、(8)又は(9)の多層フィルム。
(11)上記テトラフルオロエチレン系ポリマーの融点が、260~325℃である、(8)~(10)のいずれかの多層フィルム。
(12)上記ポリイミドのガラス転移点が、300~380℃である、(8)~(11)のいずれかの多層フィルム。
(13)上記フィルムの吸水率が、0.3%以下である、(8)~(12)のいずれかの多層フィルム。
(14)上記フィルムの剥離強度が、10N/cm以上である、(8)~(13)のいずれかの多層フィルム。
(15)ポリイミドフィルム層の表面に、熱溶融性のテトラフルオロエチレン系ポリマーのパウダー及び熱分解性ポリマーを含む液状組成物を配置し、加熱して、上記テトラフルオロエチレン系ポリマーを含む層を形成し、上記ポリイミドフィルム層と、上記ポリイミドフィルム層の表面に形成されたテトラフルオロエチレン系ポリマーを含む層とを有する多層フィルムを得る、多層フィルムの製造方法。
(16)上記熱分解性ポリマーが、(メタ)アクリル系ポリマーである、(15)の製造方法。
(17)上記テトラフルオロエチレン系ポリマーが、ペルフルオロ(アルキルビニルエーテル)に基づく単位を含むテトラフルオロエチレン系ポリマーである、(15)又は(16)の製造方法。
(18)上記テトラフルオロエチレン系ポリマーが、極性官能基を有するポリマー、又は、全単位に対してペルフルオロ(アルキルビニルエーテル)に基づく単位を2.0~5.0モル%含み、極性官能基を有さないポリマーである、(15)~(17)のいずれかの製造方法。
(19)上記熱分解性ポリマーが、側鎖に下式(1)~(5)で表されるいずれか1種の基を有する(メタ)アクリル系ポリマーである、(15)~(18)のいずれかの製造方法。
式(1)-C(O)-OC(-R11)(-R12)(-R13)
式(2)-C(O)-OCH(-R21)(-OR22)
式(3)-C(O)-O-Q3-O-CF(CF3)(-R31)
式(4)-C(O)-O-Q4-O-C(CF3)(=C(-R41)(-R42))
式(5)-C(O)-OC(CF3)2(-R51)
式中の記号は、下記の意味を示す。
R11、R12及びR13は、R11、R12及びR13がそれぞれ独立にアルキル基又はアリール基であるか、R11及びR12が水素原子でありR13がアリール基であるか、R11及びR12がそれぞれ独立に水素原子又はアルキル基でありR13がアルコキシ基であるか、R11が水素原子又はアルキル基でありR12及びR13が共同してアルキレン基を形成する基である。
R21及びR22は、R21がアルキル基でありR22はフルオロアルキル基であるか、共同してアルキレン基を形成する基である。
Q3及びQ4は、それぞれ独立にアルキレン基である。
R31は、ペルフルオロアルケニル基である。
R41及びR42は、それぞれ独立にペルフルオロアルキル基である。
R51は、アルキル基又はシクロアルキル基である。
(20)上記ポリイミドフィルム層のポリイミドが、イミド基密度が0.35以下であるポリイミドである、(15)~(19)のいずれかの製造方法。
(21)上記ポリイミドフィルム層のポリイミドが、2個以上のアリーレン基が連結基を介して連結された構造を有する芳香族ジアミン、又は、脂肪族ジアミンに基づく単位を含む、ポリイミドである、(15)~(20)のいずれかの製造方法。
(22)上記ポリイミドフィルム層のポリイミドが、芳香族テトラカルボン酸の酸二無水物に基づく単位を含み、上記芳香族テトラカルボン酸の酸二無水物が、2つの無水フタル酸構造が連結基を介して連結された構造を有する、(15)~(21)のいずれかの製造方法。
(23)上記液状組成物が、ポリイミド又はポリイミド前駆体を含む、(15)~(22)のいずれかの製造方法。
(24)ポリイミドフィルム層と、上記ポリイミドフィルム層の両面に、熱溶融性のテトラフルオロエチレン系ポリマー及び熱分解性ポリマーを含む層とを有する、多層フィルム。
(25)上記ポリイミドフィルム層のポリイミドが、イミド基密度が0.35以下であるポリイミドである、(24)の多層フィルム。
(26)上記テトラフルオロエチレン系ポリマーが、ペルフルオロ(アルキルビニルエーテル)に基づく単位を含むテトラフルオロエチレン系ポリマーである、(24)又は(25)の多層フィルム。
(27)上記テトラフルオロエチレン系ポリマーが、極性官能基を有するポリマー、又は、全単位に対してペルフルオロ(アルキルビニルエーテル)に基づく単位を2.0~5.0モル%含み、極性官能基を有さないポリマーである、(24)~(26)のいずれかの多層フィルム。
(28)上記層が、さらに芳香族ポリマーを含む、(24)~(27)のいずれかの多層フィルム。
(29)上記層が、上記熱分解性ポリマー由来の熱分解物を含む、(24)~(28)のいずれかの多層フィルム。
また、本発明によれば、層間の密着性に優れる多層フィルムの製造方法、及び多層フィルムが得られる。
「ガラス転移点(以下、「Tg」とも記す。)を有する」とは、固体動的粘弾性(以下、「DMA」とも記す。)法でポリマーを分析した際に、Tgが測定可能であることを意味する。
「ポリマーのTg」は、DMA法でポリマーを分析して測定される値である。
「テトラフルオロエチレン系ポリマー」とは、テトラフルオロエチレンに基づく単位(以下、「TFE単位」とも記す。)を含むポリマーであり、単に「TFE系ポリマー」とも記す。
「熱溶融性のテトラフルオロエチレン系ポリマー」とは、示差走査熱量測定(以下、「DSC」とも記す。)法で測定した際に、ポリマーが硬化することなく融解するものを意味する。
「ポリマーの溶融温度(融点)」は、示差走査熱量測定(DSC)法で測定したポリマーの融解ピークの最大値に対応する温度である。
「難塑性変形性」とは、ベースフィルムを塑性変形させた際に応力が増加していく特性、又は塑性変形させた際に必要な応力が大きい特性を意味し、ASTM D882に従って、ベースフィルムの引張弾性率を測定した際の「15%ひずみ時応力」の値で規定する。
「パウダーのD90」は、同様にして測定される、パウダーの体積基準累積90%径である。
なお、D50及びD90は、レーザー回折・散乱式粒度分布測定装置(堀場製作所社製、LA-920測定器)を用い、パウダーを水中に分散させて測定した値である。
「金属箔の表面の十点平均粗さ(Rzjis)」は、JIS B 0601:2013の附属書JAで規定される値である。
加熱に伴うPI層1の収縮は、PI層1の緻密化を促し、耐水性等の物性を向上する反面、皺が発生する原因ともなり層間の密着性と多層フィルムの穴あけ加工性とを低下させてしまう。つまり、収縮をコントロールしつつ、これらの物性を具備した緻密な多層フィルムを製造するのは困難であった。
かかる作用機構により、本法1によると、密着性、及び穴あけ加工性に優れ、皺が発生し無いか極めて少ない、緻密な多層フィルムが得られると考えられる。
この場合、加熱におけるPI層1の軟化とパウダーの溶融とが一層バランスして進行しやすいだけでなく、PI層1とTFE系ポリマー層1がより高度に密着して、得られる多層フィルムの物性(高剥離強度、耐水性、低線膨張性等)が向上しやすい。
芳香族性ポリイミドとしては、ジアミンとカルボン酸二無水物とを反応させてポリアミック酸を合成し、このポリアミック酸を熱イミド化法又は化学イミド化法によりイミド化して得られるポリイミドが挙げられる。
PI層1の15%ひずみ時応力は、225MPa以上が好ましく、245MPa以上がより好ましい。PI層1の15%ひずみ時応力は、580MPa以下が好ましい。
かかるPI層1は、降伏強度が高く、難塑性変形性であり、得られる多層フィルムの線膨張係数を低減させ、それに皺が発生するのをより確実に防止できる。
TFE系ポリマーのTgは、75~125℃が好ましく、80~100℃がより好ましい。
水酸基含有基は、アルコール性水酸基を含む基が好ましく、-CF2CH2OH又は-C(CF3)2OHが好ましい。
カルボニル基含有基は、カルボニル基(>C(O))を含む基であり、カルボキシル基、アルコキシカルボニル基、アミド基、イソシアネート基、カルバメート基(-OC(O)NH2)、酸無水物残基(-C(O)OC(O)-)、イミド残基(-C(O)NHC(O)-等)又はカーボネート基(-OC(O)O-)が好ましい。
TFE系ポリマーがカルボニル基含有基を有する場合、TFE系ポリマーにおけるカルボニル基含有基の数は、主鎖炭素数1×106個あたり、10~5000個が好ましく、50~4000個がより好ましく、100~2000個がさらに好ましい。この場合、TFE系ポリマーがPI層1と相互作用しやすく、得られる多層フィルムの剥離強度が向上しやすい。また、得られる多層フィルムの線膨張係数を低減させ、それに皺が発生するのをより確実に防止できる。なお、TFE系ポリマーにおけるカルボニル基含有基の数は、ポリマーの組成又は国際公開2020/145133号に記載の方法によって定量できる。
なお、TFE系ポリマー(1)は、TFE単位、PAVE単位及び極性官能基を有するモノマーに基づく単位を含むことが好ましい。
TFE系ポリマー(1)又は(2)は、そのパウダーが液中分散性に優れるだけでなく、TFE系ポリマー層1の形成において、微小球晶を形成しやすく、PI層1との密着性が一層向上しやすい。
また、極性官能基を有するモノマーは、無水イタコン酸、無水シトラコン酸又は5-ノルボルネン-2,3-ジカルボン酸無水物(別称:無水ハイミック酸;以下、「NAH」とも記す。)が好ましい。
TFE系ポリマー(1)の具体例としては、国際公開第2018/16644号に記載されるポリマーが挙げられる。
TFE系ポリマー(2)におけるPAVE単位の含有量は、全単位に対して、2.1モル%以上が好ましく、2.2モル%以上がより好ましい。
なお、TFE系ポリマー(2)が極性官能基を有さないとは、ポリマー主鎖を構成する炭素原子数の1×106個あたり、ポリマーが有する極性官能基の数が、500個未満であることを意味する。上記極性官能基の数は、100個以下が好ましく、50個未満が特に好ましい。上記極性官能基の数の下限は、通常、0個である。
TFE系ポリマー(2)は、ポリマー鎖の末端基として極性官能基を生じない、重合開始剤や連鎖移動剤等を使用して製造してもよく、極性官能基を有するFポリマー(重合開始剤に由来する極性官能基をポリマーの主鎖の末端基に有するFポリマー等)をフッ素化処理して製造してもよい。フッ素化処理の方法としては、フッ素ガスを使用する方法(特開2019-194314号公報等を参照)が挙げられる。
パウダーのD50は、10μm以下が好ましく、6μm以下がより好ましく、4μm以下がさらに好ましい。パウダーのD50は、0.01μm以上が好ましく、0.1μm以上がより好ましく、1μm以上がさらに好ましい。また、パウダーのD90は、10μm以下が好ましい。
無機物の例としては、酸化物、窒化物、金属単体、合金及びカーボンが好ましく、酸化ケイ素(シリカ)、酸化ベリリウム、酸化セリウム、アルミナ、ソーダアルミナ、酸化マグネシウム、酸化亜鉛、酸化チタン等の金属酸化物、窒化ホウ素、ステアナイト及びメタ珪酸マグネシウムがより好ましく、シリカ及び窒化ホウ素がさらに好ましく、シリカが特に好ましい。
異なるポリマーの例としては、芳香族ポリマーが挙げられる。芳香族ポリマーは、スチレンエラストマーのような芳香族エラストマー、芳香族ポリイミド、芳香族マレイミド、芳香族ポリアミック酸が挙げられる。
無機物又は異なるポリマーを含むTFE系ポリマーのパウダーは、TFE系ポリマーをコアとし、上記成分をシェルに有するコアシェル構造を有するか、TFE系ポリマーをシェルとし、上記成分をコアに有するコアシェル構造を有するのが好ましい。かかるコアシェル構造を有するパウダーは、例えば、TFE系ポリマーの粒子と、上記成分の粒子とを衝突又は凝集により合着させて得られる。
液状組成物は、液状分散媒を含むのが好ましい。
液状分散媒は、25℃で液状の、上記パウダーの分散媒である。液状分散媒は、1種を単独で使用してもよく、2種以上を併用してもよい。
液状分散媒の沸点は、125~250℃が好ましい。この範囲において、液状組成物から液状分散媒を揮発させる際に、上記パウダーが、高度に流動して緻密にパッキングし、その結果、緻密なTFE系ポリマー層が形成されやすい。
液状分散媒は、非プロトン性の極性媒体であるのが好ましい。
液状分散媒は、液状組成物の液物性(粘度、チキソ比等)の調整と各成分の高度な相互作用との観点から、エステル、ケトン及びアミドが好ましく、γ-ブチロラクトン、メチルエチルケトン、シクロヘキサノン、N,N-ジメチルホルムアミド及びNMPがより好ましい。
AR系ポリマーの5%質量減少温度は、260~600℃が好ましい。この場合、AR系ポリマーの分解ガス(気泡)やAR系ポリマー自体の反応に伴う副生物によるガス(気泡)による、TFE系ポリマー層1の界面荒れを効果的に抑制でき、TFE系ポリマー層1のPI層1に対する接着性が一層向上しやすい。
AR系ポリマーが熱可塑性であれば、その可塑性により、TFE系ポリマー層1中のAR系ポリマーの分散性がより向上し、緻密かつ均一なTFE系ポリマー層1が形成されやすい。その結果、TFE系ポリマー層1のPI層1に対する密着性と、多層フィルムの物性(UV吸収性等)とが向上しやすい。
熱可塑性のAR系ポリマーは、熱可塑性ポリイミドが好ましい。熱可塑性ポリイミドとは、イミド化が完了した、イミド化反応がさらに生じないポリイミドを意味する。
熱可塑性のAR系ポリマーのTgは、200~500℃が好ましい。
熱硬化性のAR系ポリマーとしては、熱硬化性芳香族ビスマレイミド樹脂が好ましい。 AR系ポリマーの具体例としては、「HPC」シリーズ(日立化成社製)等の芳香族性ポリアミドイミド、「ネオプリム」シリーズ(三菱ガス化学社製)、「スピクセリア」シリーズ(ソマール社製)、「Q-PILON」シリーズ(ピーアイ技術研究所製)、「WINGO」シリーズ(ウィンゴーテクノロジー社製)、「トーマイド」シリーズ(T&K TOKA社製)、「KPI-MX」シリーズ(河村産業社製)、「ユピア-AT」シリーズ(宇部興産社製)等の芳香族性ポリイミドが挙げられる。
この場合、TFE系ポリマー層1中でTFE系ポリマーとAR系ポリマーとが均一に分散して多層フィルムの物性が向上しやすいだけでなく、高温環境下において、TFE系ポリマーとAR系ポリマーとが高度に相互作用して、フィルムの耐熱性がより向上しやすい。
界面活性剤は、ノニオン性であるのが好ましい。
界面活性剤の親水部位は、ノニオン性の官能基(アルコール性水酸基、オキシアルキレン基等)を含む分子鎖が好ましい。
界面活性剤の疎水部位は、アルキル基、アセチレン基、シロキサン基又は含フッ素基を含む分子鎖が好ましく、シロキサン基を含む分子鎖が特に好ましい。換言すれば、界面活性剤は、アセチレン系界面活性剤、シリコーン系界面活性剤及びフッ素系界面活性剤が好ましく、シリコーン系界面活性剤がより好ましい。
かかる界面活性剤の具体例としては、「フタージェント」シリーズ(ネオス社製)、「サーフロン」シリーズ(AGCセイミケミカル社製)、「メガファック」シリーズ(DIC社製)、「ユニダイン」シリーズ(ダイキン工業社製)、「BYK-347」、「BYK-349」、「BYK-378」、「BYK-3450」、「BYK-3451」、「BYK-3455」、「BYK-3456」(ビックケミー・ジャパン株式会社社製)、「KF-6011」、「KF-6043」(信越化学工業株式会社製)が挙げられる。
これらの他の材料は、液状組成物に溶解してもよく、溶解しなくてもよい。
低温領域での保持は、1段階で実施してもよく、異なる温度にて2段階以上で実施してもよい。
この際の温度の保持時間は、30秒~5分間が好ましく、1~2分間がより好ましい。 この際の雰囲気は、常圧下、減圧下のいずれの状態であってよい。また、上記雰囲気は、酸化性ガス(酸素ガス等)雰囲気、還元性ガス(水素ガス等)雰囲気、不活性ガス(希ガス、窒素ガス)雰囲気のいずれであってもよい。
PI層1の厚さに対する、TFE系ポリマー層1の厚さの比は、得られるフィルムの耐水性及び電気特性の観点から、0.4以上が好ましく、1以上がより好ましい。上限は、5以下が好ましい。上記した作用機構により、本法1によれば、層間の密着性が高まるため、かかる比が高く、TFE系ポリマー層1が厚い多層フィルムが容易に得られやすい。
PI層1の厚さは、100μm以下が好ましく、75μm以下がより好ましい。下限は、10μm以上が好ましい。TFE系ポリマー層1の厚さは、100μm以下が好ましく、75μm以下がより好ましい。下限は、10μm以上が好ましい。
本フィルム1におけるTFE系ポリマー及びPI1の範囲は、好適な範囲も含めて、本法1におけるそれと同様である。
本フィルム1におけるTFE系ポリマー層1は、さらに芳香族ポリマーを含むのが好ましい。芳香族ポリマーとしては、本法1における芳香族ポリマーと同様のものが挙げられる。
本フィルム1の剥離強度は、10N/cm以上が好ましく、15N/cm以上がより好ましく、20N/cm以上がさらに好ましい。この場合、本フィルム1をプリント基板材料、金属導体の被覆材料(電線等の被覆材料)として好適に使用できる。本フィルム1の剥離強度の上限は、100N/cmである。
本フィルム1の吸水率は、0.3%以下が好ましく、0.1%以下がより好ましい。この場合、本フィルム1は、水蒸気がより透過しにくく、長期にわたって優れた絶縁性を発揮するため、特に、金属導体の被覆材料として好適に使用できる。本フィルム1の吸水率の下限は、0%である。
本フィルム1の厚さ等の好適な範囲は、本法1により得られる多層フィルムと同様である。
本フィルム1は、PI層1の両面にTFE系ポリマー層1を有するのが、ハイエンドな電子部材(プリント基板材料、電線被覆材料等)に使用する観点から好ましい。
本フィルム1は、TFE系ポリマー層1の表面の接着性に優れるため、他の基材と容易かつ強固に接合できる。他の基材としては、金属箔、金属導体が挙げられる。
金属箔を構成する金属としては、銅、銅合金、ステンレス鋼、ニッケル、ニッケル合金(42合金も含む)、アルミニウム、アルミニウム合金、チタン、チタン合金が挙げられる。
金属箔としては、銅箔が好ましく、表裏の区別のない圧延銅箔又は表裏の区別のある電解銅箔がより好ましく、圧延銅箔がさらに好ましい。圧延銅箔は、表面粗さが小さいため、金属張積層体をプリント配線板に加工した場合でも、伝送損失を低減できる。また、圧延銅箔は、炭化水素系有機溶剤に浸漬し圧延油を除去してから使用するのが好ましい。
金属箔の表面は、粗化処理されていてもよい。粗化処理の方法としては、粗化処理層を形成する方法、ドライエッチング法、ウエットエッチング法が挙げられる。
金属箔の厚さは、金属張積層体の用途において充分な機能が発揮できる厚さであればよい。金属箔の厚さは、20μm未満が好ましく、2~15μmがより好ましい。
また、金属箔の表面は、その一部又は全部がシランカップリング剤により処理されていてもよい。
熱プレスにおけるプレス温度は、310~400℃が好ましい。
熱プレスは、気泡混入を抑制し、酸化による劣化を抑制する観点から、20kPa以下の真空度で行うのが好ましい。
また、熱プレス時には上記真空度に到達した後に昇温することが好ましい。上記真空度に到達する前に昇温すると、TFE系ポリマー層1が軟化した状態、すなわち一定程度の流動性、密着性がある状態にて圧着されてしまい、気泡の原因となる場合がある。
熱プレスにおける圧力は、金属箔の破損を抑制しつつ、TFE系ポリマー層1と金属箔とを強固に密着させる観点から、0.2~10MPaが好ましい。
プリント基板は、例えば、金属張積層体における金属箔をエッチング等によって所定のパターンの導体回路(パターン回路)に加工する方法や、金属張積層体を電解めっき法(セミアディティブ法(SAP法)、モディファイドセミアディティブ法(MSAP法)等)によってパターン回路に加工する方法を使用して製造できる。
プリント基板の製造においては、パターン回路を形成した後に、パターン回路上に層間絶縁膜を形成し、層間絶縁膜上にさらに導体回路を形成してもよい。層間絶縁膜は、上記液状組成物によって形成してもよい。
プリント基板の製造においては、パターン回路上にソルダーレジストを積層してもよい。ソルダーレジストは、上記液状組成物によって形成してもよい。
プリント基板の製造においては、パターン回路上にカバーレイフィルムを積層してもよい。
金属導体の構成材料は、銅、銅合金、アルミニウム、アルミニウム合金が好ましい。これらの金属は、優れた導電性を有するためである。
また、金属導体の横断面形状は、円形であってもよく、矩形であってもよい。
本フィルム1の一方の表面に金属導体を配置し、本フィルム1で金属導体を被覆することにより被覆金属導体を製造できる。
かかる被覆金属導体の製造方法としては、本フィルム1を細幅の帯状に切断してテープを作製し、このテープを金属導体の周囲に螺旋状に卷回して製造する方法が挙げられる。また、金属導体の周囲にテープを卷回した後、さらにその周囲にテープを重ねて卷回してもよい。なお、テープは、ラッピングマシーン等を用いて金属導体の周囲に卷回してもよい。
PI層2の表面に、パウダーを含む液状組成物を塗布し、加熱してTFE系ポリマー層2を形成する場合、その熱履歴により、PI層2に含まれるポリイミドが少なからず変性するため、PI層2は必然的に変形(収縮)する。本発明者らは、このPI層2の変形が、両層の密着性を低下させると考えた。
熱分解性ポリマーは、液状組成物において、パウダーの分散を促し、その均一分散性を向上させている。そのため、PI層2の表面に液状組成物を配置し、加熱すると、パウダーの緻密なパッキングが進行し、さらにパウダーが溶融焼成し、高均質なTFE系ポリマー層2が形成され、PI層2との密着性が向上する。
本法2についてさらに記載する。
芳香族ジアミンとしては、本法1と同様の芳香族ジアミンが挙げられる。
また、PI層2のPIは、脂肪族ジアミンに基づく単位を含むことが好ましい。脂肪族ジアミンとしては、1,2-エチレンジアミン、1,3-プロピレンジアミン、1,4-ブタンジアミン、1,5-ペンタンジアミン、1,6-ヘキサンジアミン、1,7-ヘプタンジアミン、1,8-オクタンジアミン、2-メチル-1,8-オクタンジアミン、1,9-ノナンジアミン、1,10-デカンジアミン、1,11-ウンデカンジアミン、1,12-ドデカンジアミンが挙げられる。
ジアミンは、1種を単独で使用しても、2種以上を併用してもよい。
PI層2のPIは、Tgを有するのが好ましい。本法2におけるPIの好ましい態様は、本法1におけるPI1のそれと同様である。この場合、隣接する層同士の間の密着性、及び穴あけ加工性に優れ、皺が発生し無いか極めて少ない多層フィルムを得やすい。
なお、本法2におけるTFE系ポリマーの定義及び範囲は、上述したとおりである。
したがって、本法2で得られる多層フィルムは、TFE系ポリマー層2が、熱分解性ポリマー由来の熱分解物を含んでいてもよい。
熱分解性の(メタ)アクリル系ポリマーは、側鎖にフルオロアルキル基又はフルオロアルケニル基を有するのが好ましい。
フルオロアルキル基又はフルオロアルケニル基の炭素数は、4~16が好ましい。また、フルオロアルキル基又はフルオロアルケニル基の炭素原子-炭素原子間には、エーテル性酸素原子が挿入されていてもよい。
オキシアルキレン基は、1種のオキシアルキレン基から構成されていてもよく、2種以上のオキシアルキレン基から構成されていてもよい。後者の場合、種類の違うオキシアルキレン基は、ランダム状に配置されていてもよく、ブロック状に配置されていてもよい。
オキシアルキレン基は、オキシエチレン基又はオキシプロピレン基が好ましく、オキシエチレン基が特に好ましい。
(メタ)アクリル系ポリマーが熱分解して、これら親水基を有する化合物が界面に偏析することにより、TFE系ポリマー層2とPI層2との密着性が向上する。また、本法2により得られる多層フィルムをプリント基板材料として用いる場合、TFE系ポリマー層2の表面に銅箔などの金属箔を貼着するが、これら親水基を有する化合物がTFE系ポリマー層2の表面に偏析することにより、金属箔との接着性が向上する。
式(1)-C(O)-OC(-R11)(-R12)(-R13)
式(2)-C(O)-OCH(-R21)(-OR22)
式(3)-C(O)-O-Q3-O-CF(CF3)(-R31)
式(4)-C(O)-O-Q4-O-C(CF3)(=C(-R41)(-R42))
式(5)-C(O)-OC(CF3)2(-R51)
式中の記号は、下記の意味を示す。
R21及びR22は、R21がアルキル基でありR22はフルオロアルキル基であるか、共同してアルキレン基を形成する基である。
Q3及びQ4は、それぞれ独立にアルキレン基である。
R31は、ペルフルオロアルケニル基である。
R41及びR42は、それぞれ独立にペルフルオロアルキル基である。
R51は、アルキル基又はシクロアルキル基である。
式中の記号は、下記の意味を示す。
X11は、水素原子、塩素原子又はメチル基を示す。
X12は、水素原子、フッ素原子、メチル基又はトリフルオロメチル基を示す。
Q5は、アルキレン基又はオキシアルキレン基を示す。
R61は、ペルフルオロアルキル基又はペルフルオロアルケニル基を示す。
X11及びX12は、それぞれ独立に、水素原子又はメチル基であることが好ましい。
Q5及びR61における炭素含有基の炭素数は、それぞれ独立に、1~16であることが好ましい。
Q5は、-CH2CH2-、-CH2CH2CH2CH2-、-CH2CH2O-又は-CH2CH2CH2CH2O-であることが好ましい。
R61は、炭素数1~6のペルフルオロアルキル基又は炭素数1~12のペルフルオロアルケニル基であることが好ましく、-(CF2)4F、-(CF2)6F又は-OCF(CF3)C(=C(CF3)2)(CF(CF3)2)であることが特に好ましい。
式(1)で表される基を有する熱分解性ポリマーのフッ素含有量は、10~45質量%が好ましく、15~40質量%が特に好ましい。
式(1)で表される基を有する熱分解性ポリマーは、ノニオン性であることが好ましい。
式(1)で表される基を有する熱分解性ポリマーの質量平均分子量は、2000~80000が好ましく、6000~20000が特に好ましい。
式(2)で表される基の具体例としては、式-C(O)-O-CH(CH3)(-OR22)で表される基が挙げられる。
R22はフルオロアルキル基であり、フッ素原子が直接結合した炭素数が1~6のフルオロアルキル基が好ましく、炭素数が4~6のフルオロアルキル基がより好ましく、炭素数が6のフルオロアルキル基が特に好ましい。
Q6は、-(CH2)2-又は-(CH2)4-である。
式(4)で表される基の具体例としては、下式(10)で表される基が挙げられる。
式(10)-C(O)-O-Q7-O-C(CF3)(=C(-CF(CF3)2)2)
Q7は炭素数2又は4のアルキレン基である。
液状組成物におけるTFE系ポリマーの含有量は、10質量%以上が好ましく、25質量%以上がより好ましい。TFE系ポリマーの含有量は、50質量%以下が好ましく、40質量%以下がより好ましい。
液状組成物における熱分解性ポリマーの含有量は、0.1質量%以上が好ましく、1質量%以上がより好ましい。熱分解性ポリマーの含有量は、20質量%以下が好ましく、5質量%以下がより好ましい。
液状組成物は、ポリイミド、ポリイミド前駆体又はビスマレイミドを含んでもよく、ポリイミド又はポリイミド前駆体を含むのが好ましい。なお、ポリイミドの前駆体とは、TFE系ポリマー層2の形成における加熱において、ポリイミドを形成する化合物であり、ポリアミック酸が挙げられる。以下、ポリイミドと記載した場合、ポリイミド前駆体も包含する。
ポリイミド又はビスマレイミドは、芳香族性ポリイミド又は芳香族性ビスマレイミドが好ましい。この場合、TFE系ポリマー層2の表層に存在するポリイミド又はビスマレイミドがPI層2と相互作用する。具体的には、TFE系ポリマー層2とPI層2との界面付近に存在する、ポリイミド又はビスマレイミドの芳香族環とPIの芳香族環とがスタッキングするため、TFE系ポリマー層2のPI層2に対する密着性が向上すると考えられる。
また、TFE系ポリマー層2が、芳香族性ポリイミド又は芳香族性マレイミドを含む場合、本法2で得られる多層フィルムは、剥離強度と、UV吸収性(すなわちUV加工性)とに優れやすい。
ポリイミドが熱可塑性であれば、その加熱時の可塑性の発現により、TFE系ポリマー層2中のポリイミドの分散性がより向上し、緻密かつ均一なTFE系ポリマー層2が形成されやすい。その結果、TFE系ポリマー層2のPI層2に対する密着性が向上しやすい。
熱可塑性のポリイミドとは、イミド化が完了した、イミド化反応がさらに生じないポリイミドを意味する。
熱硬化性のポリイミドとしては、ポリイミド前駆体(ポリアミック酸等)のイミド化反応により形成される可塑性を有さないポリイミドが好ましい。
ビスマレイミドは、熱硬化性の芳香族性ビスマレイミド樹脂が好ましい。この場合、TFE系ポリマー層2の線膨張性が一層低下し、フィルムの反りが抑制されやすい。
液状組成物をPI層2へ配置するには、PI層2の表面に、液状組成物を塗布すればよい。液状組成物の塗布方法としては、本法1における液状組成物の塗布方法と同様の方法が挙げられる。
低温領域の温度での保持は、1段階で実施してもよく、異なる温度にて2段階以上で実施してもよい。
焼成領域の温度は、TFE系ポリマーの溶融温度以上が好ましく、300~380℃が特に好ましい。
焼成領域の温度に保持する時間は、30秒~5分間が好ましく、1~2分間が特に好ましい。
本法2で得られる多層フィルムの厚さ及び各層の厚さの好ましい範囲は、本法1で得られる多層フィルムの厚さ及び各層の厚さのそれと同様である。
本フィルム2におけるTFE系ポリマー及びPIの範囲は、好適な範囲も含めて、本法2におけるそれと同様である。
本フィルム2におけるTFE系ポリマー層2は、熱分解性ポリマー由来の熱分解物を含むのが好ましい。この場合、本フィルム2における隣接する層同士の間の接着性が向上しやすく、本フィルム2が耐水性に優れやすい。
本フィルム2の吸水率は、0.1%以下が好ましく、0.07%以下がより好ましく、0.05%以下がさらに好ましい。この場合、本フィルム2は、水蒸気がより透過し難く、長期にわたって優れた絶縁性を発揮するため、特に、金属導体の被覆材料として好適に使用できる。本フィルム2の吸水率の下限は、0%である。
本法2の多層フィルムは、TFE系ポリマー層2の表面の接着性に優れるため、他の基材と容易かつ強固に接合できる。他の基材としては、金属箔、金属導体が挙げられる。
本法2の多層フィルムは、両面のTFE系ポリマー層2に金属箔を貼着して金属張積層体としてもよい。このような金属張積層体は、金属箔を加工すればプリント基板に容易に加工できる。
[実施例1]
<<使用材料>>
<PIフィルム>
PIフィルム11:FS-100(製品名、SKC Kolon PI社製)、厚さ25μm、Tg=315℃、引張弾性率=8.0GPa
PIフィルム12:UPILEX(製品名、宇部興産社製)、厚さ25μm、Tg=350℃、引張弾性率=9.1GPa
PIフィルム13:FG-100(製品名、PI Advanced Materials社製)、厚さ25μm、Tg=330℃、引張弾性率=10.0GPa
TFE系ポリマー11:TFE単位、PPVE単位及びNAH単位を、この順に98.0モル%、1.9モル%、0.1モル%含むポリマー(溶融温度:300℃)
TFE系ポリマー12:TFE単位及びPPVE単位を、この順に98.5モル%、1.5モル%含むポリマー(溶融温度:305℃)
なお、TFE系ポリマー11は、カルボニル基含有基を、主鎖炭素数1×106個あたり、1000個有し、TFE系ポリマー12は、40個有する。
<TFE系ポリマーのパウダー>
パウダー11:TFE系ポリマー11のパウダー(平均粒径(D50):1.9μm)
パウダー12:TFE系ポリマー12のパウダー(平均粒径(D50):1.5μm)
熱可塑性芳香族ポリイミド11:3,3’4,4’-ベンゾフェノンテトラカルボン酸二無水物及び3,3’4,4’-ビフェニルテトラカルボン酸二無水物と、2,4-ジアミノトルエン及び2,2-ビス{4-(4-アミノフェノキシ)フェニル}プロパンとのブロックコポリマー
<ポリマー分散剤>
(メタ)アクリル系ポリマー11:ペルフルオロアルケニル基を有する(メタ)アクリレートとポリオキシエチレンモノグリコール基を有する(メタ)アクリレートのコポリマー
N-メチル-2-ピロリドン(NMP)を液状分散媒とする、40質量%のパウダー11と4質量%の(メタ)アクリル系ポリマー11とを含む、液状組成物11を調製した。
液状組成物11に、熱可塑性芳香族ポリイミド11のワニス(溶媒:NMP)を添加して、さらに、0.5質量%の熱可塑性芳香族ポリイミド11を含む、液状組成物12を調製した。
<多層フィルム>
[例1-1]
PIフィルム11の一方の面に、液状組成物12を小径グラビアリバース法で塗布し、通風乾燥炉(炉温:150℃)に3分間で通過させて、NMPを除去して乾燥被膜を形成した。さらに、他方の面にも、同様に、液状組成物12を塗布、乾燥し、乾燥被膜を形成した。
次いで、両面に乾燥被膜が形成されたPIフィルム11を、遠赤外線炉(炉温:320℃)に5分間で通過させて、パウダー11を溶融焼成させた。これにより、PIフィルム11の両面にTFE系ポリマー11及び熱可塑性芳香族ポリイミドを含むTFE系ポリマー層(厚さ:25μm)を形成し、TFE系ポリマー層、PIフィルム11、TFE系ポリマー層がこの順に直接形成された多層フィルム1を得た。
パウダー11をパウダー12に変更した以外は、例1-1と同様にして多層フィルム12を得た。
[例1-3]
PIフィルム11をPIフィルム12に変更した以外は、例1-1と同様にして多層フィルム13を得た。
[例1-4]
液状組成物12を液状組成物11に変更した以外は、例1-1と同様にして多層フィルム14を得た。
溶融焼成温度を300℃に変更した以外は、例1-1と同様にして多層フィルム15を得た。
[例1-6]
溶融焼成温度を350℃に変更した以外は、例1-1と同様にして多層フィルム16を得た。
[例1-7]
溶融焼成温度を360℃に変更した以外は、例1-1と同様にして多層フィルム17を得た。
PIフィルム11の両面にTFE系ポリマー11を溶融押出成形して得られるフィルム(厚さ:50μm)をそれぞれ対向させて、320℃にて15分間、真空プレスし、TFE系ポリマー層、PIフィルム11、TFE系ポリマー層がこの順に直接形成された多層フィルム18を得た。
[例1-9]
PIフィルム11をPIフィルム13に変更した以外は、例1-1と同様にして多層フィルム19を得た。
<外観>
得られた多層フィルムを平滑なガラスの表面に静置し、反り(うねり)の発生の有無を確認し、以下の基準にて評価した。
〇:反りの発生が確認されない。
△:反りの発生が確認される。
×:反りの発生が確認されるだけでなく、皺が寄っている。
多層フィルム19は、皺の発生が無く、表面平滑性が多層フィルム中で最も高かった。
得られた多層フィルムから、12cm角に裁断した試料を作製して、下記の方法で熱収縮率を求めた。
25℃において、試料に約10cmの長さの直線を1本描き、直線の端点間距離を初期長L0とする。次いで、試料を320℃で5分間熱処理し、25℃まで冷却した後、試料上に描かれた直線の端点間の直線距離L1を測定し、下式1により熱収縮率(%)を求め、以下の基準で評価した。
熱収縮率(%)=(1-L1/L0)×100 ・・・式1
〇:熱収縮率≦2%
△:2%<熱収縮率<3%
×:熱収縮率≧3%
得られた多層フィルムから、長さ100mm、幅10mmの矩形状の試験片を切り出した。その後、試験片の長さ方向の一端から50mmの位置まで、PIフィルムとTFE系ポリマー層とを剥離した。次いで、試験片の長さ方向の一端から50mmの位置を中央にして、引張り試験機(オリエンテック社製)を用いて、引張り速度50mm/分で90度剥離させた際の、最大荷重を剥離強度(N/cm)とし、以下の基準にて評価した。
〇:剥離強度≧10N/cm
△:5N/cm<剥離強度<10N/cm
×:剥離強度≦5N/cm
得られた多層フィルムの両面に、銅箔(電解銅箔CF-T49A-DS-HD2-12、福田金属箔粉工業株式会社)を配し、340℃にて20分間、真空下でプレスし、両面銅張積層体を作製した。
レーザー加工機を使用して、それぞれの両面銅張積層体に対して、直径100μmの円周上を周回するように、波長355nmのUV-YAGレーザーを照射した。これにより、両面銅張積層体に円形の貫通孔を形成した。なお、レーザー出力を1.2W、レーザー焦点径を25μm、円周上の周回回数を20回、発振周波数を40kHzとした。
〇:貫通孔内部の層界面に、削れと剥がれが確認されない。
△:貫通孔内部の層界面に、削れが確認されるが、剥がれは確認されない。
×:貫通孔内部の層界面に、削れと剥がれが確認される。
JISK7209:2000Aの方法に準じて吸水率を測定した。
得られた多層フィルムを、10cm角に切り出し、試験片を調製した。次に、この試験片を50℃にて24時間乾燥させ、デシケーター内で冷却した。この時点における試験片の質量を、試験片の水浸漬前質量とした。
その後、この乾燥させた試験片を、23℃にて24時間、純水に浸漬させた。その後、試験片を純水から取り出し、速やかに表面の水分を拭き取った後、1分以内に質量を測定し、試験片の水浸漬後質量とした。
〇:吸水率が0.3%以下である。
△:吸水率が0.3%超、1%未満である。
×:吸水率が1%以上である。
それぞれの評価結果を、まとめて表1に示す。
<<使用材料>>
<TFE系ポリマー>
TFE系ポリマー21:TFE単位、PPVE単位及びNAH単位を、この順に98.0モル%、1.9モル%、0.1モル%含む、極性官能基を有するポリマー(溶融温度300℃)
なお、TFE系ポリマー21は、カルボニル基含有基を、主鎖炭素数1×106個あたり、1000個有する。
<TFE系ポリマーのパウダー>
パウダー21:TFE系ポリマー21のパウダー(平均粒径(D50):2μm)
(メタ)アクリル系ポリマー21:
CH2=C(CH3)COO(CH2)4OCF(CF3)C(=C(CF3)2)(CF(CF3)2)と、CH2=C(CH3)COO(CH2)4(OCH2CH2)9OHのコポリマー
(メタ)アクリル系ポリマー22:
CH2=C(CH3)COO(CH2)2(CF2)6Fと、CH2=C(CH3)COO(CH2)4(OCH2CH2)23OHのコポリマー
<液状分散媒>
NMP:N-メチル-2-ピロリドン
PIフィルム21:酸無水物モノマーがBPDA(3,3’,4,4’-ビフェニルテトラカルボン酸二無水物)であり、ジアミンモノマーがBAFL(9,9-ビス(4-アミノフェニル)フルオレン)であるポリイミド(イミド基密度:≦0.35)のフィルム(厚さ:50μm)
なお、PIフィルム21のTgは320℃、引張弾性率は9.5GPaである。
PIフィルム22:酸無水物モノマーがBPDAであり、ジアミンモノマーがPDA(p-フェニレンジアミン)であるポリイミド(イミド基密度:>0.35)のフィルム(厚さ:50μm)
なお、PIフィルム22のTgは315℃、引張弾性率は8.2GPaである。
液状組成物21:パウダー21(30質量%)、熱可塑性ポリイミド(1質量%)、(メタ)アクリル系ポリマー21(3質量%)及びNMP(残部)を含む、パウダー分散液
液状組成物22:パウダー21(30質量%)、熱可塑性ポリイミド(1質量%)、(メタ)アクリル系ポリマー22(3質量%)及びNMP(残部)を含む、パウダー分散液
液状組成物23:パウダー21(30質量%)、(メタ)アクリル系ポリマー21(3質量%)及びNMP(残部)を含む、パウダー分散液
液状組成物24:パウダー21(30質量%)及びNMP(残部)を含む、パウダー分散液
<多層フィルム>
[例2-1]多層フィルム21の製造例
PIフィルム21の一方の表面に液状組成物21を小径グラビアリバース法で塗布し、通風乾燥炉(炉温:150℃)にて3分間乾燥させて、NMPを除去して乾燥被膜を形成した。さらに、他方の表面にも、同様に、液状組成物21を塗布、乾燥させて、乾燥被膜を形成した。
次いで、遠赤外線炉(炉温:320℃)に20分間で通過させて、パウダー21を溶融焼成させた。これにより、PIフィルム21の両方の最表面にTFE系ポリマー21及び熱可塑性ポリイミドを含むポリマー層(厚さ:25μm)を形成し、TFE系ポリマー層、PIフィルム層、TFE系ポリマー層をこの順に有する多層フィルム21を得た。
PIフィルム21をPIフィルム22に変更した以外は、例2-1と同様にして多層フィルム22を得た。
[例2-3]多層フィルム23の製造例
液状組成物21を液状組成物23に変更した以外は、例2-1と同様にして多層フィルム23を得た。
[例2-4]多層フィルム24の製造例
液状組成物21を液状組成物22に変更した以外は、例2-1と同様にして多層フィルム24を得た。
[例2-5]多層フィルム25の製造例
液状組成物21を液状組成物24に変更した以外は、例2-1と同様にして多層フィルム25を得た。
<層表面の分解物>
TFE系ポリマー層の表面を、全反射-赤外吸収スペクトル法(ATR-IR分析法)と、AFM-IR法とで分析して、検出される官能基の種類から評価し、前者の方法でカルボキシ基が、後者の方法でエーテル性酸素原子が、それぞれ検出された場合は分解物「有」、いずれも検出されない場合は分解物「無」とする。
多層フィルム21~25のそれぞれの密着性を、実施例1における密着性と同様の方法で評価した結果は、密着性の程度は、高い順に、多層フィルム21、多層フィルム22、多層フィルム23、多層フィルム24の順であり、これらの多層フィルムの密着性より多層フィルム25の密着性は低かった。
実施例1における耐水性と同様の方法で評価した。
<外観>
実施例1における外観と同様の方法で評価した。
それぞれの評価結果を、まとめて表1に示す。
Claims (15)
- ガラス転移点を有するポリイミドを含む層の表面に、熱溶融性のテトラフルオロエチレン系ポリマーのパウダーを含む液状組成物を配置し、前記テトラフルオロエチレン系ポリマーの融点超、かつ、前記ポリイミドのガラス転移点+40℃以下の温度にて加熱し、前記テトラフルオロエチレン系ポリマーを含む層を形成して、前記ポリイミドを含む層と、前記ポリイミドを含む層の表面に形成された前記テトラフルオロエチレン系ポリマーを含む層とを有する多層フィルムを得る、多層フィルムの製造方法。
- 前記テトラフルオロエチレン系ポリマーが、ペルフルオロ(アルキルビニルエーテル)に基づく単位を含むテトラフルオロエチレン系ポリマーである、請求項1に記載の製造方法。
- 前記テトラフルオロエチレン系ポリマーが、極性官能基を有するポリマー、又は、全単位に対してペルフルオロ(アルキルビニルエーテル)に基づく単位を2.0~5.0モル%含み、極性官能基を有さないポリマーである、請求項1又は2に記載の製造方法。
- 前記液状組成物が、さらに芳香族ポリマーを含む、請求項1~3のいずれか1項に記載の製造方法。
- 前記テトラフルオロエチレン系ポリマーを含む層の厚さが、100μm以下である、請求項1~4のいずれか1項に記載の製造方法。
- 前記ポリイミドを含む層の厚さに対する、前記テトラフルオロエチレン系ポリマーを含む層の厚さの比が、0.4以上である、請求項1~5のいずれか1項に記載の製造方法。
- 前記ポリイミドを含む層の両面に、前記テトラフルオロエチレン系ポリマーを含む層をそれぞれ形成する、請求項1~6のいずれか1項に記載の製造方法。
- ガラス転移点を有するポリイミドを含む層と、前記ポリイミドを含む層の両面に形成された熱溶融性のテトラフルオロエチレン系ポリマーを含む層とを有し、前記ポリイミドのガラス転移点が前記テトラフルオロエチレン系ポリマーの融点超、かつ、前記テトラフルオロエチレン系ポリマーの融点+60℃以下である、多層フィルム。
- 前記テトラフルオロエチレン系ポリマーが、ペルフルオロ(アルキルビニルエーテル)に基づく単位を含むテトラフルオロエチレン系ポリマーである、請求項8に記載の多層フィルム。
- 前記テトラフルオロエチレン系ポリマーが、極性官能基を有するポリマー、又は、全単位に対してペルフルオロ(アルキルビニルエーテル)に基づく単位を2.0~5.0モル%含み、極性官能基を有さないポリマーである、請求項8又は9に記載の多層フィルム。
- 前記テトラフルオロエチレン系ポリマーの融点が、260~325℃である、請求項8~10のいずれか1項に記載の多層フィルム。
- 前記ポリイミドのガラス転移点が、300~380℃である、請求項8~11のいずれか1項に記載の多層フィルム。
- 前記フィルムの剥離強度が、10N/cm以上である、請求項8~13のいずれか1項に記載の多層フィルム。
- ポリイミドフィルム層の表面に、熱溶融性のテトラフルオロエチレン系ポリマーのパウダー及び熱分解性ポリマーを含む液状組成物を配置し、加熱して、前記テトラフルオロエチレン系ポリマーを含む層を形成し、前記ポリイミドフィルム層と、前記ポリイミドフィルム層の表面に形成されたテトラフルオロエチレン系ポリマーを含む層とを有する多層フィルムを得る、多層フィルムの製造方法。
- ポリイミドフィルム層と、前記ポリイミドフィルム層の両面に、熱溶融性のテトラフルオロエチレン系ポリマー及び熱分解性ポリマーを含む層とを有する、多層フィルム。
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JP2011162581A (ja) * | 2010-02-04 | 2011-08-25 | Canon Inc | インクジェット用インク |
JP2015110697A (ja) * | 2013-12-06 | 2015-06-18 | 共栄社化学株式会社 | フッ素ポリマー用分散剤 |
WO2018016644A1 (ja) * | 2016-07-22 | 2018-01-25 | 旭硝子株式会社 | 液状組成物、並びに該液状組成物を使用した、フィルムおよび積層体の製造方法 |
JP2019166844A (ja) * | 2013-11-29 | 2019-10-03 | Agc株式会社 | 接着フィルム、フレキシブル金属積層板、接着フィルムの製造方法、フレキシブル金属積層板の製造方法、フレキシブルプリント基板及びフレキシブルプリント基板の製造方法 |
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JP2019166844A (ja) * | 2013-11-29 | 2019-10-03 | Agc株式会社 | 接着フィルム、フレキシブル金属積層板、接着フィルムの製造方法、フレキシブル金属積層板の製造方法、フレキシブルプリント基板及びフレキシブルプリント基板の製造方法 |
JP2015110697A (ja) * | 2013-12-06 | 2015-06-18 | 共栄社化学株式会社 | フッ素ポリマー用分散剤 |
WO2018016644A1 (ja) * | 2016-07-22 | 2018-01-25 | 旭硝子株式会社 | 液状組成物、並びに該液状組成物を使用した、フィルムおよび積層体の製造方法 |
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