WO2023224057A1 - 積層圧電フィルム - Google Patents

積層圧電フィルム Download PDF

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Publication number
WO2023224057A1
WO2023224057A1 PCT/JP2023/018369 JP2023018369W WO2023224057A1 WO 2023224057 A1 WO2023224057 A1 WO 2023224057A1 JP 2023018369 W JP2023018369 W JP 2023018369W WO 2023224057 A1 WO2023224057 A1 WO 2023224057A1
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Prior art keywords
piezoelectric film
film
less
rigidity
laminated
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Ceased
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PCT/JP2023/018369
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English (en)
French (fr)
Japanese (ja)
Inventor
正寛 芹川
誠 今治
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Kureha Corp
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Kureha Corp
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Priority to EP23807658.2A priority Critical patent/EP4507480A4/en
Priority to KR1020247037627A priority patent/KR102892441B1/ko
Priority to US18/865,500 priority patent/US20250318434A1/en
Priority to JP2024521957A priority patent/JP7730420B2/ja
Priority to CN202380038375.4A priority patent/CN119138126A/zh
Publication of WO2023224057A1 publication Critical patent/WO2023224057A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/02—Forming enclosures or casings
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/704—Piezoelectric or electrostrictive devices based on piezoelectric or electrostrictive films or coatings
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/88—Mounts; Supports; Enclosures; Casings
    • H10N30/883—Additional insulation means preventing electrical, physical or chemical damage, e.g. protective coatings
    • 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
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • 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
    • B32B27/16—Layered products comprising a layer of synthetic resin specially treated, e.g. irradiated
    • 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
    • B32B27/304—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
    • 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
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • 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
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/022—Mechanical properties
    • 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
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/50—Piezoelectric or electrostrictive devices having a stacked or multilayer structure
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/85—Piezoelectric or electrostrictive active materials
    • H10N30/857—Macromolecular compositions
    • 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
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/538—Roughness
    • 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
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/732—Dimensional properties
    • B32B2307/737—Dimensions, e.g. volume or area
    • B32B2307/7375—Linear, e.g. length, distance or width
    • B32B2307/7376—Thickness
    • 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
    • B32B2457/00—Electrical equipment

Definitions

  • the present invention relates to a laminated piezoelectric film.
  • touch sensors have been introduced to electronic devices such as smartphones and tablets, and are used as human-machine interfaces that enable intuitive operation.
  • a touch sensor operates an electronic device by detecting a two-dimensional position touched with a finger or a pen (for example, see Patent Document 1).
  • touch sensors that detect pressing force have been developed to increase input information and improve operability. For example, there are methods of detecting the pressing force based on changes in capacitance or changes in resistance using pressure-sensitive rubber when the casing is distorted, and methods that detect changes in the electric charge of a piezoelectric material.
  • a piezoelectric film for a touch panel that can detect such pressing force (Z coordinate)
  • a fluororesin piezoelectric material whose main component is polyvinylidene fluoride or polyvinylidene fluoride-tetrafluoroethylene copolymer is known. There is.
  • film stretching treatment or thermal poling treatment may be performed.
  • smoothness tends to decrease due to large waviness on the surface, and there is a risk of problems occurring during the lamination process in the manufacturing process of laminates using the piezoelectric film.
  • the piezoelectric sensitivity of the laminate may be reduced.
  • the inventor of the present invention has conducted extensive studies on the above-mentioned problem, and has discovered that a protective film with high rigidity (hereinafter, the product of the tensile modulus of elasticity of the film and the thickness of the film is referred to as "rigidity”) is laminated on the surface of the piezoelectric film. It was found that smoothness could be improved by
  • the surface of the piezoelectric film is smooth (smoothness), and heat treatment may be performed in the process of laminating a conductive layer on the laminated film.
  • the laminated piezoelectric film must not curl during heat treatment (high thermal stability), and must not wrinkle due to stress during transportation (high rigidity).
  • the present invention has been made in view of the above problems, and aims to provide a laminated piezoelectric film that has high rigidity, high thermal stability, and excellent smoothness.
  • the present inventor provides a laminated piezoelectric film equipped with a protective film, in which B/A of the rigidity B of the protective film and the rigidity A of the piezoelectric film satisfies a specific range, and the thickness of the protective film satisfies a specific range.
  • the inventors have discovered that the above problems can be solved by forming a laminated piezoelectric film, and have completed the present invention.
  • the present invention relates to the following.
  • the present invention provides a laminated piezoelectric film comprising a piezoelectric film and a protective film laminated on one surface of the piezoelectric film, wherein the rigidity B of the protective film is 1.0 of the rigidity A of the piezoelectric film.
  • the invention relates to a laminated piezoelectric film in which the protective film has a thickness of 50 ⁇ m or more and 200 ⁇ m or less.
  • the thickness of the protective film is 1.5 times or more the thickness of the piezoelectric film. It is preferable that the rigidity B of the protective film is 3.0 times or more and 20 times or less the rigidity A of the piezoelectric film. It is preferable that the surface unevenness of the surface of the piezoelectric film opposite to the side on which the protective film is laminated is 80 ⁇ m or less.
  • the piezoelectric film contains polyvinylidene fluoride as a main component.
  • a laminated piezoelectric film with high rigidity and excellent thermal stability and smoothness can be provided.
  • FIG. 1 is a cross-sectional view schematically showing a laminated piezoelectric film 1 which is an embodiment of the laminated piezoelectric film of the present invention.
  • FIG. 2 is a cross-sectional view schematically showing a laminated piezoelectric film 2 which is another embodiment of the laminated piezoelectric film of the present invention.
  • the present embodiment an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings, but the present invention is not limited thereto and within the scope of the gist thereof. Various modifications are possible.
  • laminate may mean that each layer is laminated in order, and other layers may be laminated between each layer.
  • the laminated piezoelectric film according to the present invention is a laminated piezoelectric film comprising a piezoelectric film and a protective film laminated on one surface of the piezoelectric film, wherein the rigidity B of the protective film is the same as that of the piezoelectric film.
  • the rigidity A is 1.0 times or more and 20 times or less, and the thickness of the protective film is 50 ⁇ m or more and 200 ⁇ m or less.
  • the rigidity B of the protective film when the rigidity B of the protective film is 1.0 to 20 times the rigidity A of the piezoelectric film, it is easy to obtain a laminated piezoelectric film with excellent thermal stability and smoothness.
  • the rigidity of the film indicates its resistance to deformation, and by setting the rigidity B of the protective film and the rigidity A of the piezoelectric film within a specific range, the protective film smoothes the undulations on the surface of the piezoelectric film, and the piezoelectric film It is presumed that it reduces the degree of surface unevenness and also suppresses curling of the laminated piezoelectric film due to processing heat.
  • the rigidity B of the protective film is 1.0 to 20 times the rigidity A of the piezoelectric film, and the thickness of the protective film is 50 to 200 ⁇ m.
  • the rigidity of the protective film is less than 1.0 times the rigidity of the piezoelectric film, it will be difficult to suppress waviness on the surface of the piezoelectric film by the rigidity of the protective film, and the degree of unevenness on the surface of the piezoelectric film will increase, which is not preferable. Further, from the viewpoint of production processes such as transportation and winding, the rigidity of the protective film may be 10 times or less than the rigidity of the piezoelectric film.
  • the rigidity of the protective film is preferably 1.5 times or more and 20 times or less, more preferably 2.5 times or more and 20 times or less, even more preferably 3.0 times or more and 20 times or less, and 5.0 times the rigidity of the piezoelectric film.
  • the tensile modulus of the film may vary depending on the measurement direction, in this specification, the tensile modulus of the protective film, piezoelectric film, and laminated piezoelectric film means its minimum value.
  • the above tensile modulus is a value measured in accordance with JIS K 7127 and calculated based on 10.3 of JIS K 7161-1, and specifically, by the method described in the Examples below. can be measured.
  • the curl height of a laminated piezoelectric film upon heating is a measure of the thermal stability of the film.
  • the maximum height of the film that is reached by curving the film from the film grounding position is called the curl height, and the smaller the curl height, the higher the thermal stability.
  • the curl height is preferably 20 mm or less, more preferably 15 mm or less, and even more preferably 10 mm or less.
  • the curl height of the laminated piezoelectric film can be measured by the method described in Examples below.
  • the curl height is considered to be more than 20 mm.
  • the curl height of the laminated piezoelectric film can be adjusted as appropriate by, for example, examining the thickness and tensile modulus of the protective film, the thickness and tensile modulus of the piezoelectric film, and the difference in linear expansion coefficient between the protective film and the piezoelectric film. Can be done.
  • the thickness of the laminated piezoelectric film is preferably 50 ⁇ m or more and 300 ⁇ m or less, more preferably 100 ⁇ m or more and 300 ⁇ m or less, and even more preferably 150 ⁇ m or more and 250 ⁇ m or less.
  • the thickness of the film is 50 ⁇ m or more, the film tends to have sufficient rigidity. Further, it is preferable that the thickness of the film is 300 ⁇ m or less from the viewpoint of production processes such as transportation and winding.
  • the thickness of the protective film is preferably 50 ⁇ m or more and 200 ⁇ m or less, more preferably 70 ⁇ m or more and 200 ⁇ m or less, even more preferably 90 ⁇ m or more and 150 ⁇ m or less, and particularly preferably 110 ⁇ m or more and 150 ⁇ m or less.
  • the thickness of the protective film is 50 ⁇ m or more, it tends to have higher rigidity and can easily obtain excellent thermal stability and smoothness.
  • the thickness of the piezoelectric film is preferably 10 ⁇ m or more and 200 ⁇ m or less, more preferably 20 ⁇ m or more and 200 ⁇ m or less, even more preferably 30 ⁇ m or more and 120 ⁇ m or less, and particularly preferably 30 ⁇ m or more and 80 ⁇ m or less.
  • the thickness of the film is 10 ⁇ m or more, the strength is likely to be sufficient.
  • it is 200 ⁇ m or less, transparency tends to be sufficient and it is easy to use it for optical purposes.
  • the thickness of the protective film is preferably 1.5 times or more and 10 times or less, more preferably 2.0 times or more and 10 times or less, the thickness of the piezoelectric film. If it is 1.5 times or more, the rigidity of the protective film becomes dominant in the rigidity of the laminated piezoelectric film.
  • the protective film is not subjected to a treatment to increase piezoelectricity as is done with piezoelectric films. Therefore, since the protective film has excellent thermal stability and smoothness, the rigidity of the protective film becomes dominant in the rigidity of the laminated piezoelectric film, so the laminated piezoelectric film can obtain excellent thermal stability and smoothness. Cheap.
  • the tensile modulus of the protective film is preferably 1.0 GPa or more and 5.0 GPa or less, more preferably 2.0 GPa or more and 5.0 GPa or less, and even more preferably 3.0 GPa or more and 5.0 GPa or less.
  • the tensile modulus of the protective film may be 5.0 GPa or less.
  • the tensile modulus of the piezoelectric film is preferably 0.5 GPa or more and 3.0 GPa or less, more preferably 1.0 GPa or more and 3.0 GPa or less, even more preferably 1.5 GPa or more and 3.0 GPa or less, and 1.5 GPa or more and 2.0 GPa or less. The following are particularly preferred. Within the above numerical range, piezoelectricity tends to be sufficient.
  • the rigidity of the laminated piezoelectric film is preferably 100 N/mm or more and 1000 N/mm or less, more preferably 200 N/mm or more and 1000 N/mm or less, even more preferably 300 N/mm or more and 1000 N/mm or less, and 400 N/mm or more and 1000 N/mm or less. is particularly preferred.
  • the rigidity of the laminated piezoelectric film is 100 N/mm or more, the film tends to have excellent thermal stability and smoothness.
  • the rigidity of the protective film is preferably 100 N/mm or more and 1000 N/mm or less, more preferably 150 N/mm or more and 1000 N/mm or less, even more preferably 300 N/mm or more and 1000 N/mm or less, and 400 N/mm or more and 1000 N/mm or less. Particularly preferred.
  • a laminated piezoelectric film using the film tends to have excellent thermal stability and smoothness.
  • the rigidity of the piezoelectric film is preferably 10 N/mm or more and 200 N/mm or less, more preferably 50 N/mm or more and 200 N/mm or less, and even more preferably 50 N/mm or more and 150 N/mm or less.
  • a laminated piezoelectric film using the film tends to have high piezoelectricity.
  • the degree of surface unevenness on the surface of the piezoelectric film opposite to the side on which the protective film is laminated is preferably 80 ⁇ m or less, more preferably 60 ⁇ m or less, even more preferably 40 ⁇ m or less, and particularly preferably 30 ⁇ m or less.
  • the degree of surface unevenness on the surface of the film is 100 ⁇ m or less, excellent smoothness can be easily obtained, problems in the lamination process using the film can be reduced, and the piezoelectric sensitivity of the laminate obtained in the process can be improved. will improve.
  • the surface unevenness can be measured by the method described in Examples below.
  • the degree of surface unevenness in this specification is not a value based on minute unevenness on the surface, but a value based on undulations and wrinkles on the surface.
  • the surface unevenness can be adjusted as appropriate by, for example, examining the thickness and tensile modulus of the protective film, and the thickness and tensile modulus of the piezoelectric film.
  • FIG. 1 is a cross-sectional view schematically showing a laminated piezoelectric film 1, which is an embodiment of the laminated piezoelectric film.
  • a protective film 31 is laminated on one surface of the piezoelectric film 11.
  • FIG. 2 is a cross-sectional view schematically showing a laminated piezoelectric film 2, which is another embodiment of the laminated piezoelectric film.
  • the laminated piezoelectric film 2 differs from the laminated piezoelectric film 1 in that it includes an adhesive layer 21 between the piezoelectric film 11 and the protective film 31.
  • the piezoelectric film 11 is a film (thin film) having piezoelectricity (the property of converting applied force into voltage or the property of converting applied voltage into force).
  • the piezoelectric film 11 is generally made of a polarized polymer compound that can exhibit piezoelectricity by orienting molecular dipoles through a polarization treatment called thermal poling treatment, or a chiral polymer compound that can exhibit piezoelectricity by applying a stretching treatment to a chiral polymer compound.
  • a polarization treatment called thermal poling treatment
  • a chiral polymer compound that can exhibit piezoelectricity by applying a stretching treatment to a chiral polymer compound.
  • stretched chiral polymer compounds that can express the following.
  • the polarized polymer compound include fluororesins; vinylidene cyanide polymers; vinyl acetate polymers; odd-numbered nylons such as nylon 9 and nylon 11; and polyurea.
  • the stretched chiral polymer compound examples include helical chiral polymer compounds such as polylactic acid; polyhydroxycarboxylic acids such as polyhydroxybutyrate; and cellulose derivatives. These can be used alone or in combination of two or more.
  • fluororesins are preferred because the smoothness of the surface of the piezoelectric film tends to decrease and the smoothness improving effect of the present invention is easily exhibited. If the piezoelectric film is a uniaxially stretched film, the surface smoothness tends to be low, and the smoothness improving effect of the present invention is likely to be exhibited. Further, when the piezoelectric film is made of a fluororesin, if the degree of polarization is large, the surface smoothness tends to decrease, and the smoothness improving effect of the present invention is likely to be exhibited.
  • fluororesin examples include polyvinylidene fluoride (PVDF), vinylidene fluoride copolymers (for example, vinylidene fluoride/trifluoroethylene copolymer, vinylidene fluoride/trifluoroethylene/chlorotrifluoroethylene copolymer, Hexafluoropropylene/vinylidene fluoride copolymer, perfluorovinyl ether/vinylidene fluoride copolymer, tetrafluoroethylene/vinylidene fluoride copolymer, hexafluoropropylene oxide/vinylidene fluoride copolymer, hexafluoropropylene oxide/ Examples include tetrafluoroethylene/vinylidene fluoride copolymer, hexafluoropropylene/tetrafluoroethylene/vinylidene fluoride copolymer); tetrafluoroethylene polymer; chlor
  • polyvinylidene fluoride or a vinylidene fluoride copolymer as the main component, and to use polyvinylidene fluoride as the main component. is more preferable.
  • the mass of components constituting a certain polymer compound is 50% by mass or more based on the total mass of the polymer compound (resin) constituting the piezoelectric film, the polymer compound is used as the main component. It is called.
  • the piezoelectric film 11 may further contain commonly used additives (fillers, surfactants, etc.).
  • the protective film 31 is not particularly limited as long as it has the above-mentioned characteristics, and may include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), polypropylene (PP), and polyethylene.
  • Polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), polypropylene (PP), and polyethylene.
  • Polyolefin resins such as (PE), halogen-containing polymers such as polyvinyl chloride (PVC) and polyvinylidene fluoride (PVDF), acrylic polymers such as polymethyl methacrylate, polystyrene, and styrene-methyl methacrylate copolymers. Examples include styrenic polymers such as.
  • PET or PP is preferred, and PET is more preferred, from the viewpoint of better achieving the effects of the present
  • the laminated piezoelectric film according to the present invention may include an adhesive layer.
  • the laminated piezoelectric film 2 includes an adhesive layer 21 between the piezoelectric film 11 and the protective film 31. That is, the piezoelectric film 11 and the protective film 31 may be bonded together with the adhesive layer 21 interposed therebetween.
  • the adhesive layer is not particularly limited as long as it can be easily peeled off from the piezoelectric film together with the protective film, but for example, acrylic resin, rubber resin such as natural rubber, synthetic rubber, etc. can be used.
  • the laminated piezoelectric film according to the present invention can be used for piezoelectric panels including capacitive type and resistive type touch panels, pressure sensors, actuators for haptic devices, piezoelectric vibration power generation devices, flat speakers, etc. Suitable for use in devices.
  • the device may further include a general display panel unit such as an LCD under the piezoelectric film.
  • the above device is suitably used for smartphones, personal digital assistants, tablet PCs, notebook computers, medical equipment, car navigation systems, and the like.
  • the laminated piezoelectric film according to this embodiment can be manufactured by a method including (1) a step of manufacturing a piezoelectric film, and (2) a step of laminating a protective film.
  • the method of manufacturing a piezoelectric film is not particularly limited, and can be manufactured, for example, by the following method.
  • the piezoelectric film can be obtained through a process of polarizing a film containing a fluororesin.
  • the film containing the fluororesin may be a stretched film or an unstretched film.
  • a film containing a fluororesin can be produced by any method such as melt extrusion or solution casting. Among these, it is preferable that a film containing a fluororesin be manufactured by a melt extrusion method from the viewpoint of easily obtaining a piezoelectric film having a thickness of a predetermined thickness or more.
  • a fluororesin and any additives are heated and melted in a cylinder of an extruder, and then extruded from a die to obtain a film.
  • the obtained film has a structure in which ⁇ -type crystals (the main chain has a helical structure) and ⁇ -type crystals (the main chain has a planar zigzag structure) are mixed.
  • ⁇ -type crystals have a large polarized structure.
  • the stretching direction may be the TD direction or the MD direction, and is more preferably the MD direction.
  • the stretching method is not particularly limited, and known stretching methods such as a tenter method and a drum method can be used.
  • the stretching ratio may be, for example, 3.0 times or more and 6.0 times or less.
  • the stretching ratio is 3.0 times or more, the thickness and polarizability of the film can be easily adjusted to a more appropriate range.
  • the stretching ratio is 3.0 times or more, the dislocation of ⁇ -type crystals becomes more sufficient, and not only higher piezoelectricity is easily expressed, but also transparency can be further improved.
  • the stretching ratio is 6.0 times or less, breakage due to stretching can be further suppressed.
  • the obtained stretched film is polarized.
  • the polarization process can be performed, for example, by applying a DC voltage between the ground electrode and the needle electrode.
  • the voltage may be adjusted depending on the thickness of the stretched film, and may be, for example, 1 kV or more and 50 kV or less.
  • a piezoelectric film can be obtained by polarizing a stretched film.
  • the protective film may be a commercially available product or may be manufactured.
  • the protective film is preferably a film with a high tensile modulus from the viewpoint of improving the surface smoothness of the piezoelectric film.
  • a protective film having the tensile modulus and type described above can be used.
  • the method of laminating the protective film is not particularly limited, and examples thereof include a method of laminating the protective film and the piezoelectric film via an adhesive layer using a laminator or the like.
  • the protective film has self-adhesion, the protective film and the piezoelectric film may be bonded together without using an adhesive layer.
  • a protective film on which an adhesive layer is formed may be bonded to the piezoelectric film, or a protective film may be bonded after forming an adhesive layer on the piezoelectric film.
  • the tensile modulus of each of the piezoelectric film, protective film, and laminated piezoelectric film was measured in accordance with JIS K 7127. Using a test piece cut to 10 mm x 100 mm so that the long side was parallel to the longitudinal direction (MD), the measurement was performed at a tensile speed of 50 mm/min and a distance between chucks of 50 mm. The tensile modulus at this time was calculated based on 10.3 of JIS K 7161-1. In addition, the tensile modulus was calculated in the same manner using test pieces cut so that the long sides were parallel to other directions such as the transverse direction (TD), but in all Examples and Comparative Examples. The tensile modulus in the longitudinal direction was the smallest.
  • cur height A test piece obtained by cutting a laminated piezoelectric film into 10 cm square pieces was heat-treated by placing it in an oven set at 50° C. for 1 minute. Thereafter, the lifting amount of the four corners of the heat-treated test piece in the vertical direction was measured, and the maximum height was defined as the curl height (mm).
  • the surface roughness ( ⁇ m) of the laminated piezoelectric film was measured using a 3D shape measuring machine VR-5000 (manufactured by Keyence Corporation). Place a test piece cut to the same size on a 20 cm x 30 cm stainless steel plate (1 mm thick) with the piezoelectric film side facing up, and place the center of the long side of the test piece so as not to apply tension. I held it in place with a magnet and then secured the four corners with tape. As preprocessing, a reference plane was set using a designated area (75 mm x 140 mm), and noise removal was set to medium. Measurements were performed by photographing the designated area with a low-magnification camera.
  • the mode was multi-line roughness mode, the number of lines was 11, the interval was 100 lines, the area was horizontal lines and vertical lines, and there was no cutoff.
  • the measurement was carried out, and the arithmetic mean height Ra of 22 lines in total was determined.
  • Ta The test piece was reset each time and measured a total of 3 times, and the arithmetic mean value of the 3 measurements was determined as the degree of surface unevenness.
  • Examples 1-2 and Comparative Examples 1-4 A resin film (thickness: 120 ⁇ m) formed from polyvinylidene fluoride (manufactured by Kureha Co., Ltd.) having an inherent viscosity of 1.1 dl/g was uniaxially stretched to a stretching ratio of 4.2 times. After stretching, the film was polarized by applying a DC voltage increasing from 0 kV to 12.0 kV between the ground electrode and the needle-shaped electrode to obtain a piezoelectric film. The film after the polarization treatment was further heat-treated at 130° C. for 1 minute to obtain a piezoelectric film having a thickness of 40 ⁇ m.
  • the tensile modulus of the piezoelectric film was 1812 MPa, and the product of the thickness and the tensile modulus was 72.5 N/mm.
  • the laminated film in which the adhesive layer was formed on the protective film shown in Table 1 and the piezoelectric film were bonded together using a laminator, and then wound into a roll to obtain a laminated piezoelectric film.
  • the laminator was set at a line speed of 5 m/min and a laminating roll contact pressure of approximately 0.3 N.
  • the product of the thickness and tensile modulus of the laminated piezoelectric film was high, the curl height was low, and the degree of surface roughness was low. Therefore, it was confirmed that according to the present invention, a laminated piezoelectric film having high rigidity and excellent thermal stability and smoothness can be obtained.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Laminated Bodies (AREA)
PCT/JP2023/018369 2022-05-18 2023-05-17 積層圧電フィルム Ceased WO2023224057A1 (ja)

Priority Applications (5)

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EP23807658.2A EP4507480A4 (en) 2022-05-18 2023-05-17 LAMINATED PIEZOELECTRIC FILM
KR1020247037627A KR102892441B1 (ko) 2022-05-18 2023-05-17 적층 압전 필름
US18/865,500 US20250318434A1 (en) 2022-05-18 2023-05-17 Layered piezoelectric film
JP2024521957A JP7730420B2 (ja) 2022-05-18 2023-05-17 積層圧電フィルム
CN202380038375.4A CN119138126A (zh) 2022-05-18 2023-05-17 层叠压电膜

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TWI903935B (zh) * 2023-12-21 2025-11-01 日商吳羽股份有限公司 積層壓電體及其製造方法
WO2026029139A1 (ja) * 2024-07-31 2026-02-05 株式会社クレハ フッ素系樹脂圧電フィルムおよびその製造方法

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JPH05324203A (ja) 1992-05-22 1993-12-07 Fujitsu Ltd 静電容量型タッチパネル
WO2016076071A1 (ja) * 2014-11-14 2016-05-19 三井化学株式会社 高分子圧電フィルム
JP2016219804A (ja) * 2015-05-22 2016-12-22 ダイキン工業株式会社 有機圧電フィルム
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TWI903935B (zh) * 2023-12-21 2025-11-01 日商吳羽股份有限公司 積層壓電體及其製造方法
WO2026029139A1 (ja) * 2024-07-31 2026-02-05 株式会社クレハ フッ素系樹脂圧電フィルムおよびその製造方法

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TWI855689B (zh) 2024-09-11
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JP7730420B2 (ja) 2025-08-27
US20250318434A1 (en) 2025-10-09
TW202412343A (zh) 2024-03-16
EP4507480A4 (en) 2025-07-09
JPWO2023224057A1 (https=) 2023-11-23
KR102892441B1 (ko) 2025-11-27
EP4507480A1 (en) 2025-02-12

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