WO2022270364A1 - 有機圧電フィルム、積層体、および有機圧電フィルムの製造方法 - Google Patents

有機圧電フィルム、積層体、および有機圧電フィルムの製造方法 Download PDF

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WO2022270364A1
WO2022270364A1 PCT/JP2022/023838 JP2022023838W WO2022270364A1 WO 2022270364 A1 WO2022270364 A1 WO 2022270364A1 JP 2022023838 W JP2022023838 W JP 2022023838W WO 2022270364 A1 WO2022270364 A1 WO 2022270364A1
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film
organic piezoelectric
raw material
piezoelectric film
group
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French (fr)
Japanese (ja)
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栞里 内山
大輔 真井
智也 水森
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大阪有機化学工業株式会社
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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
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • 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

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  • the present invention relates to an organic piezoelectric film, a laminate, and a method for manufacturing an organic piezoelectric film.
  • Organic piezoelectric films have flexibility and can be applied to various applications.
  • various piezoelectric elements such as piezoelectric sensors, transducers, and infrared pyroelectric sensors, and touch pressure-detectable touch panels. , pressure sensors, haptic devices, vibration generators, planar speakers, etc.
  • Patent Document 1 describes an organic piezoelectric film having a coefficient of variation of piezoelectric constant d33 of 50% or less as an organic piezoelectric film with small in-plane variation in piezoelectricity
  • Patent Document 2 describes a withstand voltage defect value is 300 V/ ⁇ m or more and is said to have high electrical insulation and voltage resistance.
  • an object of the present invention is to provide an organic piezoelectric film with small in-plane variations in piezoelectricity and a reduced number of defects, and a laminate comprising this organic piezoelectric film.
  • Another object of the present invention is to provide a manufacturing method capable of easily manufacturing an organic piezoelectric film with small in-plane variations in piezoelectricity and a reduced number of defects.
  • the present inventors conducted various studies on the method of manufacturing an organic piezoelectric film. As a result, the present inventors have found that the above problems can be solved by subjecting a raw material film coated with a cover film satisfying specific conditions to polarization treatment, and have completed the present invention.
  • the present invention includes the following preferred aspects.
  • at least one of the coefficient of variation of the piezoelectric constant d33 and the coefficient of variation of the piezoelectric constant d31 is 0.01 or less;
  • At least one of the piezoelectric constant d33 and the piezoelectric constant d31 is 1 pC /N or more, and
  • the polarized fluoropolymer is at least one selected from the group consisting of vinylidene fluoride/trifluoroethylene copolymers, vinylidene fluoride/tetrafluoroethylene copolymers, and vinylidene fluoride homopolymers.
  • At least part of one side of a raw material film containing a polymer having piezoelectricity by being polarized is represented by the formula: ln(C ⁇ ) ⁇ 17 [wherein C is capacitance (pF) and ⁇ is conductivity (S/m)]
  • a covering step of covering with a cover film that satisfies A raw material coated with the cover film such that the application electrode and the cover film are opposed to a polarizing device comprising an application electrode and a ground electrode, and the ground electrode and the other surface of the raw material film are connected.
  • a method for producing an organic piezoelectric film, comprising a polarization step of placing the film and performing a polarization treatment.
  • the fixing step includes A coating step of forming a coating film by coating a substrate with a coating liquid containing an organic material having piezoelectricity by being polarized; including a raw material film forming step of obtaining a raw material film from the coating film, Performing the coating step on the raw material film obtained in the raw film forming step, The method for producing an organic piezoelectric film according to [12]. [14] At least part of the force resisting the shrinkage stress of the raw material film generated in the polarization step is imparted by applying tension to at least one of the raw material film and the cover film, [10] to [ 13].
  • an organic piezoelectric film having a small in-plane variation in piezoelectricity and a reduced number of defects, a laminate comprising the organic piezoelectric film, and a method for producing the organic piezoelectric film are provided. provided.
  • FIG. 1 is a schematic diagram of a manufacturing apparatus 1A related to a manufacturing method of an organic piezoelectric film 9A according to Embodiment 1.
  • FIG. FIG. 11 is a schematic diagram of a manufacturing apparatus 1B related to a method of manufacturing an organic piezoelectric film 9B according to Embodiment 2;
  • FIG. 11 is a schematic diagram of a manufacturing apparatus 1C related to a manufacturing method of an organic piezoelectric film 9C according to Embodiment 3;
  • FIG. 11 is a schematic diagram of a manufacturing apparatus 1D related to a manufacturing method of an organic piezoelectric film 9D according to Embodiment 4;
  • FIG. 11 is a schematic process diagram of a method for manufacturing an organic piezoelectric film 9E according to Embodiment 5;
  • the organic piezoelectric film of the present invention is a film having piezoelectricity, for example, a film containing a piezoelectric polymer described later.
  • at least one of the coefficient of variation of the piezoelectric constant d33 and the coefficient of variation of the piezoelectric constant d31 which are one of the indicators of piezoelectric properties, is 0.01 or less
  • the piezoelectric constant d33 and the piezoelectric At least one of the constants d31 is 1 pC/N or more, and the number of defects per 1 m 2 is less than 0.2.
  • the organic piezoelectric film of the present invention has smaller in-plane variations in piezoelectricity and a reduced number of defects compared to conventional organic piezoelectric films. Moreover, in one preferred embodiment, the organic piezoelectric film of the present invention has few wrinkles on the surface.
  • the piezoelectric constant d33 of the organic piezoelectric film of the present invention is 1 pC/N or more. In applications that require a piezoelectric constant d33 as piezoelectric properties, if the piezoelectric constant d33 is less than 1 pC/N, sufficient piezoelectric properties cannot be obtained.
  • the piezoelectric constant d33 may vary depending on the application or mode of use of the organic piezoelectric film. N or more, even more preferably 15 pC/N or more, particularly preferably 17 pC/N or more, even more preferably 20 pC/N or more, very preferably 22 pC/N or more, and very preferably 25 pC/N or more. .
  • the piezoelectric constant d33 of the organic piezoelectric film of the present invention is determined by the following method, including the examples described later.
  • a measuring device a piezometer system (product name: LPF-02) manufactured by Lead Techno Co., Ltd., or an equivalent product thereof is used.
  • the contact area of the stylus of this measuring device with the organic piezoelectric film is 0.03 mm 2 .
  • the piezoelectric constant d33 is measured at 9 points on the organic piezoelectric film selected by eliminating arbitrariness, and the arithmetic mean value is taken as the piezoelectric constant d33 of the organic piezoelectric film.
  • selecting 9 points on the film by eliminating arbitrariness can be achieved by selecting 9 points such that they are separated from each other by 15 mm or more in a range of 50 mm in length and 50 mm in width, for example.
  • Arbitrariness means that the coefficient of variation, which will be described later, is intended to be small.
  • the measured value of the piezoelectric constant d 33 is a positive value or a negative value depending on one side and the other side (front side and back side) of the film to be measured, but in this specification, the piezoelectric constant d As the value of 33 , its absolute value is described.
  • the piezoelectric constant d31 of the organic piezoelectric film of the present invention is 1 pC/N or more. In applications that require a piezoelectric constant d31 as piezoelectric properties, if the piezoelectric constant d31 is less than 1 pC/N, sufficient piezoelectric properties cannot be obtained.
  • the piezoelectric constant d31 may vary depending on the application or mode of use of the organic piezoelectric film. N or more, even more preferably 8 pC/N or more, particularly preferably 10 pC/N or more, even more preferably 11 pC/N or more, extremely preferably 12 pC/N or more, and extremely more preferably 13 pC/N or more. .
  • the piezoelectric constant d31 of the organic piezoelectric film of the present invention is determined by the following method. Select 10 locations on the organic piezoelectric film selected by eliminating arbitrariness, and gold electrodes are applied to both sides of the 10 locations using a resistance heating vapor deposition device manufactured by Cryovac (product name: CVZ-RHD300-08). was formed to form 10 lamination regions. After that, each laminated region was cut out to form 10 laminated bodies, and the piezoelectric constant d31 of each laminated body was measured. As a measuring device, a piezometer system (product name: LPX-03) manufactured by Lead Techno Co., Ltd. or an equivalent thereof is used.
  • selecting 10 locations by eliminating arbitrariness on the film means that, for example, in a range of 100 mm long and 100 mm wide, the distance between the centers of the areas of 20 mm long and 5 mm wide is 15 mm or more. This can be done by selecting 10 points apart. At this time, the size of the gold electrode and thus the size of the laminate is 20 mm long and 5 mm wide. Arbitrariness means that the coefficient of variation, which will be described later, is intended to be small.
  • the variation coefficient of the piezoelectric constant d33 of the organic piezoelectric film of the present invention is the ratio of the standard deviation to the arithmetic mean of the "piezoelectric constant d33 " described above.
  • the coefficient of variation of the piezoelectric constant d31 of the organic piezoelectric film of the present invention is the ratio of the standard deviation to the arithmetic mean of the "piezoelectric constant d31 " described above. Since at least one of the variation coefficient of the piezoelectric constant d33 and the variation coefficient of the piezoelectric constant d31 of the organic piezoelectric film of the present invention is 0.01 or less, it can be said that the in-plane variation of the piezoelectricity is very small.
  • the variation coefficient of the piezoelectric constant d33 and the variation coefficient of the piezoelectric constant d31 of the organic piezoelectric film of the present invention are both preferably 0.005 or less, more preferably 0.005 or less, from the viewpoint of more easily reducing in-plane variations in piezoelectricity. is less than or equal to 0.001.
  • the organic piezoelectric film has piezoelectric properties due to the fact that the orientation directions of the dipoles in the organic piezoelectric film are aligned.
  • the magnitude of the piezoelectric constant d33 is determined by the magnitude and number of dipoles per unit area extending in the thickness direction of the organic piezoelectric film.
  • the magnitude of the piezoelectric constant d 31 is determined by the magnitude and number of dipoles per unit area extending in the direction perpendicular to the thickness direction of the organic piezoelectric film. Therefore, in an organic piezoelectric film formed of a specific material, if the composition is uniform throughout the organic piezoelectric film, the size and number of dipoles per unit area are constant in any region.
  • the fact that the variation coefficient of the piezoelectric constant d33 of this organic piezoelectric film is small (variation is small in a plurality of regions) means that the orientation direction of the dipoles is aligned in the same direction (thickness direction) in any region.
  • a defect is a portion that does not exhibit piezoelectricity in the organic piezoelectric film, and is typically a portion observed as a black spot. Reducing the number of defects also improves the in-plane uniformity of the organic piezoelectric film.
  • the size of the defect is not particularly limited, a black spot having a diameter of 0.01 mm 2 or more is defined as a defect in this specification. Defects are often observed as black spots of about 0.01 mm 2 to 1 mm 2 .
  • the number of defects in the organic piezoelectric film of the present invention is less than 0.2 per square meter. If the number of defects is 0.2 or more, the coefficient of variation of the piezoelectric constant d33 cannot be sufficiently reduced.
  • the number of defects is preferably 0.15 or less, more preferably 0.1 or less, even more preferably 0.05 or less, and particularly preferably 0.01 or less.
  • the total area of defects in the organic piezoelectric film of the present invention is preferably less than 0.2 mm 2 , more preferably 0.15 mm 2 or less per 1 m 2 from the viewpoint of easily improving the in-plane uniformity of the organic piezoelectric film. , even more preferably 0.10 mm 2 or less, particularly preferably 0.05 mm 2 or less, particularly more preferably 0.01 mm 2 or less, very preferably 0.001 mm 2 or less, very more preferably 0.0001 mm 2 or less .
  • the number of defects and the total area thereof can be determined by analysis using commercially available image analysis software or the like, and may be measured visually or with various microscopes. Further, whether or not the organic piezoelectric film has defects can be confirmed by forming electrodes on the entire surfaces of both surfaces of the organic piezoelectric film and checking whether the electrodes are electrically connected. For example, gold electrodes are formed on both sides of an organic piezoelectric film of a certain size, and continuity is confirmed using a commercially available tester or the like. If there is even one defect in the organic piezoelectric film, the electrode on one side and the electrode on the other side are electrically connected through the defect, resulting in conduction.
  • the organic piezoelectric film of the present invention has few wrinkles, which are partial unevenness, and high surface smoothness.
  • the piezoelectric constant of the wrinkled portion is likely to differ from the piezoelectric constant of the non-wrinkled portion because the thickness of the wrinkled portion is different. Therefore, the organic piezoelectric film of the present invention, which has few wrinkles, has a small in-plane variation in piezoelectricity.
  • the wrinkles of the organic piezoelectric film refer to irregularities having a maximum height or depth of 0.04 mm (40 ⁇ m) or more in the thickness direction of the piezoelectric film and a length of 2 mm or more. .
  • the convex portion on one side is often observed as a concave portion on the other side.
  • the number of wrinkles in the organic piezoelectric film of the present invention is 1 or less per 1 m 2 , more preferably 0.5 or less, and still more preferably 0.1 or less.
  • the number of wrinkles and their height and depth can be determined by analysis using commercially available image analysis software or the like, and may be measured visually.
  • An example of visual measurement includes the following. (1) In the organic piezoelectric film, the height or depth of visually recognizable wrinkles is measured with a stylus surface profilometer (manufactured by KLA-Tencor, product name: P-10).
  • Measurement conditions Rate: 100 um/sec, Range: 327 um, Stylus Radius: 2 um, Force: 1 mg
  • Rate 100 um/sec, Range: 327 um, Stylus Radius: 2 um, Force: 1 mg
  • Measurement conditions Rate: 100 um/sec, Range: 327 um, Stylus Radius: 2 um, Force: 1 mg
  • Measurement conditions Rate: 100 um/sec, Range: 327 um, Stylus Radius: 2 um, Force: 1 mg
  • Measurement conditions Rate: 100 um/sec, Range: 327 um, Stylus Radius: 2 um, Force: 1 mg
  • Measure the length of wrinkles with a height (or depth that may be measured) of 40 ⁇ m or more with a ruler. At this time, for curved wrinkles, the straight line distance from the starting point to the ending point is taken as the length of the wrinkle.
  • (3) The above (1) and (2) are performed on the front surface (or the back surface) of the organic piezoelectric film, and the number of wrinkles is determined.
  • the wrinkles that occur in the organic piezoelectric film are caused by aligning the orientation directions of the dipoles in the polymer that can have piezoelectric properties (hereinafter referred to as the raw material polymer) in the raw material film during the polarization treatment described below.
  • the orientation direction of the dipoles in the raw material polymer which had been oriented in various directions until then, moves according to the direction of the electric field (typically, the direction substantially perpendicular to the plane direction of the raw material film).
  • the orientation directions of the dipoles in each raw material polymer are aligned.
  • the inventors of the present invention have found that by applying a force that resists the aforementioned stress to the raw material film during the poling process, wrinkles can be prevented and an organic piezoelectric film with less wrinkles can be obtained.
  • the organic piezoelectric film of the present invention comprises a piezoelectric polymer.
  • a piezoelectric polymer is a polymer that exhibits piezoelectricity, and is typically derived from a raw material polymer and has dipoles aligned in the same orientation direction, which was not the same in the raw material polymer.
  • the piezoelectric polymer should exhibit desired piezoelectric properties, and it is allowed that a part of the raw material polymer remains in the organic piezoelectric film in a state that does not contribute to the exhibiting of the piezoelectric properties.
  • Raw material polymers include, for example, polarized halogen-based polymers (in particular, polarized fluorine-based polymers), polarized cyano-based polymers, amide-based polymers, odd-chain nylon-based polymers, and polyurea, and Combinations of these and the like are included.
  • the organic piezoelectric film of the present invention preferably contains a polarized fluoropolymer from the viewpoint of easily obtaining an organic piezoelectric film having a high piezoelectric constant d33 and/or a high piezoelectric constant d31 .
  • polarized fluoropolymers include polymers containing at least repeating units derived from vinylidene fluoride, such as vinylidene fluoride/trifluoroethylene copolymer, vinylidene fluoride/tetrafluoroethylene copolymer polymers, and at least one polymer selected from the group consisting of vinylidene fluoride homopolymers.
  • the polarized halogen-based polymer includes a (meth)acrylic polymer containing a structural unit derived from a (meth)acrylic monomer represented by formula (II) described later.
  • a (meth)acrylic polymer containing a structural unit derived from a (meth)acrylic monomer represented by formula (II) can be converted into a polarized halogen-based polymer by polarization treatment conditions or mixing with other piezoelectric polymers. However, it does not necessarily result in a polarized halogen-based polymer. In such a case, the (meth)acrylic polymer represented by formula (II) is not a piezoelectric polymer but a piezoelectric polymer treated as a polymer other than a piezoelectric polymer that may be contained in addition to These copolymers may contain repeating units derived from other monomers.
  • the piezoelectric constant d33 is preferably 5 pC/N or more, more preferably 10 pC/N or more, still more preferably 15 pC/N or more, and further preferably More preferably 20 pC/N or more, particularly preferably 22 pC/N or more, and even more preferably 25 pC/N or more.
  • the piezoelectric constant d31 is preferably 2 pC/N or more, more preferably 3 pC/N or more, still more preferably 5 pC/N or more, even more preferably 7 pC/N or more, and particularly preferably 13 pC/N or more. , more preferably 15 pC/N or more, particularly preferably 17 pC/N or more.
  • the organic piezoelectric film of the present invention may contain materials other than the piezoelectric polymer for the purpose of improving its physical properties.
  • materials other than the piezoelectric polymer include polymers other than piezoelectric polymers, elastomers, antioxidants, additives such as ultraviolet absorbers, thermally conductive fillers, plasticizers, powders of inorganic piezoelectric materials, and the like. is not limited to The organic piezoelectric film of the present invention may contain these other materials singly or in combination of two or more.
  • R 1 is an alkyl group having 1 to 10 carbon atoms, which may be substituted with a hydroxyl group, an alkyl group having 1 or 2 carbon atoms, and/or an alkoxy group having 1 to 6 carbon atoms; hydrocarbon groups with 3 to 12 carbon atoms, including alicyclic hydrocarbon groups with 3 to 6 carbon atoms in which at least one carbon atom may be substituted with an oxygen atom; a phenylalkylene group in which the alkylene portion has 1 to 4 carbon atoms and one —CH 2 — in the alkylene portion may be substituted with —O—, or A group represented by —((CH 2 ) m —O—) n —X [wherein m and n each represent a number of 2 or 3, and
  • alkyl group having 1 to 10 carbon atoms which may be substituted with a hydroxyl group, an alkyl group having 1 or 2 carbon atoms, and/or an alkoxy group having 1 to 6 carbon atoms
  • the number of carbon atoms in the alkyl group is , preferably 1 to 6, more preferably 1 to 4, from the viewpoint of low distortion characteristics.
  • alkyl groups can be straight or branched.
  • alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, and neopentyl groups. , 1,1-dimethylpropyl group, isoamyl group, n-hexyl group, isohexyl group, n-octyl group and the like.
  • These alkyl groups having 1 to 10 carbon atoms may be substituted with hydroxyl groups, alkyl groups having 1 or 2 carbon atoms and/or alkoxy groups having 1 to 6 carbon atoms.
  • alkyl groups having 1 to 10 carbon atoms substituted with a hydroxyl group include, for example, hydroxymethyl group, hydroxyethyl group, hydroxy n-propyl group, hydroxyisopropyl group, hydroxy n-butyl group, hydroxyisobutyl group, hydroxy tert- A butyl group and the like can be mentioned.
  • An alkyl group having 1 to 10 carbon atoms substituted with an alkyl group having 1 or 2 carbon atoms has an alkyl group having 1 to 10 carbon atoms as a main chain, and at least one hydrogen atom of the alkyl group has 1 or 2 carbon atoms.
  • alkyl groups include, for example, a 2-ethylhexyl group.
  • the group is also included in the definition of a branched alkyl group having 1 to 10 carbon atoms.
  • the number of carbon atoms in the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 2.
  • the alkyl group in the alkoxy group may also be linear or branched.
  • the alkyl group having 1 to 10 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 6 carbon atoms substituted by an alkoxy group having 1 to 6 carbon atoms.
  • Examples of such groups include, for example, methoxyethyl, ethoxyethyl and methoxybutyl groups.
  • the alkyl group having 1 to 10 carbon atoms substituted with a hydroxyl group and an alkoxy group having 1 to 6 carbon atoms is, for example, a group having a hydroxyalkoxy group having 1 to 6 carbon atoms and an alkyl group having 1 to 6 carbon atoms, specifically Examples include hydroxymethoxyethyl group, hydroxyethoxyethyl group, hydroxypropyloxypropyl group and the like.
  • an alkyl group having 1 to 6 carbon atoms which may be substituted with a hydroxyl group and/or an alkoxy group having 1 to 2 carbon atoms is preferable, and a hydroxyl group and/or a carbon number
  • An alkyl group having 1 to 4 carbon atoms which may be substituted by an alkoxy group having 1 to 2 carbon atoms is more preferable, and an alkyl group having 1 to 2 carbon atoms which may be substituted by a hydroxyl group and/or an alkoxy group having 1 to 2 carbon atoms. is more preferred.
  • Hydrocarbon groups having 3 to 12 carbon atoms including alicyclic hydrocarbon groups having 3 to 6 carbon atoms in which at least one carbon atom may be substituted with an oxygen atom
  • Alicyclic hydrocarbon groups include, for example, cyclohexane.
  • the alicyclic hydrocarbon group having 3 to 6 carbon atoms in which at least one carbon atom is substituted with an oxygen atom includes epoxy in which one carbon atom of the alicyclic hydrocarbon group having 3 carbon atoms is substituted with an oxygen atom.
  • Hydrogen atoms on these rings may be substituted with alkyl groups having 1 or 2 carbon atoms.
  • the hydrocarbon group having 3 to 12 carbon atoms including the alicyclic hydrocarbon group having 3 to 6 carbon atoms, has 1 to 4 carbon atoms, and one —CH 2 — is substituted with —O—.
  • the cyclic hydrocarbon group portion having 3 to 6 carbon atoms In this case, the position of the substituent is not particularly limited, but it is preferable that the hydrogen atom located at the portion connecting the alkylene portion and the ring structure is substituted with a methyl group or an ethyl group.
  • At least one hydrogen atom in the carbon atom located between the two oxygen atoms has 1 or 2 carbon atoms is preferably substituted with an alkyl group of Specific examples of such groups include 3-ethyl-3-oxetanylmethyl acrylate, 2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, cyclic trimethylolpropane formal acrylate, and the like. is mentioned.
  • a phenylalkylene group in which the alkylene portion has 1 to 4 carbon atoms and one —CH 2 — in the alkylene portion may be substituted with —O— such a group is preferably —(CH 2 ) k —C 6 H 5 or —(CH 2 ) k —C 6 H 5 [k is 2 or 3].
  • a methoxyethyl group is mentioned.
  • R 1 in the above formula (I) is preferably a hydroxyl group, an alkyl group having 1 or 2 carbon atoms, and/or , an alkyl group having 1 to 10 carbon atoms which may be substituted by an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 2 carbon atoms which may be substituted by an alkyl group having 1 to 2 carbon atoms.
  • 8 alkyl group particularly preferably an alkyl group having 2 to 8 carbon atoms which may be substituted with an alkyl group having 1 or 2 carbon atoms.
  • acrylic monomers satisfying the above formula (I) include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n- pentyl acrylate, isopentyl acrylate, neopentyl acrylate, 1,1-dimethylpropyl acrylate, isoamyl acrylate, n-hexyl acrylate, isohexyl acrylate, n-octyl acrylate, hydroxymethyl acrylate, hydroxyethyl acrylate, hydroxy n-propyl acrylate, Hydroxyisopropyl acrylate, hydroxy n-butyl acrylate, hydroxyisobutyl acrylate, hydroxy tert-butyl acrylate, 2-ethylhe
  • the acrylic polymer optionally contained in the organic piezoelectric film of the present invention may have only structural units derived from one type of acrylic monomer represented by the formula (I), or ) may have structural units derived from two or more acrylic monomers. Further, the acrylic polymer optionally contained in the organic piezoelectric film of the present invention may contain a structural unit derived from at least one other monomer as long as the properties of the organic piezoelectric film of the present invention are not impaired.
  • the acrylic polymer optionally contained in the organic piezoelectric film of the present invention may be a homopolymer of the acrylic monomer represented by formula (I) above, or may be a homopolymer of the acrylic monomer represented by formula (I) above. It may be a copolymer of two or more acrylic monomers, or a copolymer of at least one acrylic monomer represented by the formula (I) and at least one other monomer. There may be.
  • Other monomers that can be copolymerized with the acrylic monomer represented by formula (I) include, for example, carboxyl group-containing monomers, carboxylic acid alkyl esters other than acrylic monomers that provide structural units represented by formula (I). system monomers, amide group-containing monomers, aryl group-containing monomers, styrene-based monomers, nitrogen atom-containing monomers, fatty acid vinyl ester-based monomers, betaine monomers, and the like.
  • carboxyl group-containing monomers examples include (meth)acrylic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, and crotonic acid.
  • Carboxylic acid alkyl ester monomers other than (meth)acrylic monomers that provide the structural unit represented by formula (I) include, for example, dodecyl (meth)acrylate, stearyl (meth)acrylate, and the like, in which the number of carbon atoms in the alkyl group is Examples include alkyl acrylates having 11 to 20 carbon atoms and alkyl itaconic acid esters having an alkyl group having 1 to 4 carbon atoms such as methyl itaconate and ethyl itaconate.
  • Amide group-containing monomers include, for example, N-methyl(meth)acrylamide, N-el(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-tert-butyl(meth)acrylamide , N-octyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, and alkyl (meth)acrylamides having 1 to 8 carbon atoms in the alkyl group. .
  • aryl group-containing monomers examples include aryl (meth)acrylates having 6 to 12 carbon atoms in the aryl group such as benzyl (meth)acrylate.
  • Styrenic monomers include, for example, styrene and ⁇ -methylstyrene.
  • nitrogen atom-containing monomers examples include N-vinylpyrrolidone and N-vinylcaprolactam.
  • fatty acid vinyl ester monomers examples include vinyl acetate and vinyl propionate.
  • betaine monomers include N-acryloyloxymethyl-N,N-dimethylammoniummethyl- ⁇ -sulfobetaine, N-methacryloyloxymethyl-N,N-dimethylammoniummethyl- ⁇ -sulfobetaine, N-acryloyloxymethyl -N,N-dimethylammoniumethyl- ⁇ -sulfobetaine, N-methacryloyloxymethyl-N,N-dimethylammoniumethyl- ⁇ -sulfobetaine, N-acryloyloxymethyl-N,N-dimethylammoniumpropyl- ⁇ -sulfo betaine, N-methacryloyloxymethyl-N,N-dimethylammoniumpropyl- ⁇ -sulfobetaine, N-acryloyloxymethyl-N,N-dimethylammoniumbutyl- ⁇ -sulfobetaine, N-methacryloyloxymethyl-N,N- Dimethylammonium butyl- ⁇
  • R 2 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, wherein at least one hydrogen atom of R 2 may be substituted with a halogen atom
  • R 3 is a linear or branched alkyl group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms including an alicyclic structure having 3 to 6 carbon atoms, a phenyl group, or , represents a phenylalkylene group containing an alkylene group having 1 to 4 carbon atoms,
  • at least one carbon atom of the alkyl group, the alicyclic hydrocarbon group, the phenyl group, and the phenylalkylene group may be substituted with -O-, -N- or -S-.
  • At least one hydrogen atom of the alkyl group, the alicyclic hydrocarbon group and the alkylene group is substituted with a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, and/or an alkoxy group having 1 to 6 carbon atoms.
  • a (meth)acrylic polymer containing a structural unit derived from a (meth)acrylic monomer represented by is exemplified.
  • R 2 in formula (II) above represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, where at least one hydrogen atom of R 2 may be substituted with a halogen atom.
  • alkyl groups having 1 to 3 carbon atoms include methyl group, ethyl group and propyl group, and groups in which at least one hydrogen atom is substituted with a halogen atom may be used.
  • a halogen atom is preferably at least one atom selected from the group consisting of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, more preferably a fluorine atom and/or a chlorine atom, still more preferably a fluorine atom. is.
  • R 2 include, but are not limited to, a trifluoromethyl group, a difluoromethyl group, a monofluoromethyl group, a trifluoroethyl group, a difluoroethyl group, a monochloromethyl group, and the like.
  • R 3 in the above formula (II) is (1) a linear or branched alkyl group having 1 to 10 carbon atoms, and (2) 3 to 3 carbon atoms including an alicyclic structure having 3 to 6 carbon atoms. 12 alicyclic hydrocarbon group, (3) a phenyl group, or (4) a phenylalkylene group containing an alkylene group having 1 to 4 carbon atoms, wherein the alkyl group and the alicyclic hydrocarbon group , the phenyl group, and the phenylalkylene group, wherein at least one carbon atom may be substituted with -O-, -N- or -S-, and the alkyl group, the alicyclic hydrocarbon group and the At least one hydrogen atom of the alkylene group may be substituted with a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, and/or an alkoxy group having 1 to 6 carbon atoms, and At least one hydrogen atom on the phenyl
  • At least one hydrogen atom of R 3 may be substituted with a halogen atom means that R 3 is the above (1) linear or branched alkyl group having 1 to 10 carbon atoms.
  • at least one hydrogen atom contained in the linear or branched alkyl group may be substituted with a halogen atom, or at least one hydrogen atom of the alkyl group is a hydroxyl group, the number of carbon atoms
  • the substituted alkyl group having 1 to 6 carbon atoms and/or 1 to 6 carbon atoms At least one hydrogen atom in the alkoxy group of may be substituted with a halogen atom.
  • the halogen atom includes the atoms described above for R 2 , and the preferred description of the halogen atom for R 2 also applies to R 3 .
  • the number of carbon atoms in the alkyl group having 1 to 6 carbon atoms and the alkyl group in the alkoxy group having 1 to 6 carbon atoms may be 1 to 4, more preferably 1 to 2.
  • the alkyl group having 1 to 6 carbon atoms and the alkyl group in the alkoxy group may be linear or branched.
  • R 3 in the above formula (II) represents (1) a linear or branched alkyl group having 1 to 10 carbon atoms
  • the number of carbon atoms in the alkyl group is represented by the above formula (II). It is preferably 1 to 6, more preferably 1 to 4, from the viewpoint of productivity of the (meth)acrylic monomer.
  • alkyl groups can be straight or branched. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, and neopentyl groups.
  • At least one carbon atom of the alkyl group having 1 to 10 carbon atoms may be substituted with -O-, -N- or -S-, and at least one hydrogen atom of the alkyl group having 1 to 10 carbon atoms is , a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, and/or an alkoxy group having 1 to 6 carbon atoms.
  • alkyl groups having 1 to 10 carbon atoms substituted with a hydroxyl group include, for example, hydroxymethyl group, hydroxyethyl group, hydroxy n-propyl group, hydroxyisopropyl group, hydroxy n-butyl group, hydroxyisobutyl group, hydroxy tert- A butyl group and the like can be mentioned.
  • An alkyl group having 1 to 10 carbon atoms substituted with an alkyl group having 1 to 6 carbon atoms has an alkyl group having 1 to 10 carbon atoms as a main chain, and at least one hydrogen atom of the alkyl group has 1 to 6 carbon atoms. is a group substituted with an alkyl group of If the number of carbon atoms in the main chain alkyl group portion is 1 to 10, the number of carbon atoms in the entire alkyl group may exceed 10. Examples of such alkyl groups include, for example, a 2-ethylhexyl group. In addition, in the case of a group having not more than 10 carbon atoms as a whole alkyl group, the group is also included in the definition of a branched alkyl group having 1 to 10 carbon atoms.
  • the alkyl group having 1 to 10 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 6 carbon atoms substituted by an alkoxy group having 1 to 6 carbon atoms.
  • Examples of such groups include, for example, methoxyethyl, ethoxyethyl and methoxybutyl groups.
  • the alkyl group having 1 to 10 carbon atoms substituted with a hydroxyl group and an alkoxy group having 1 to 6 carbon atoms is, for example, a group having a hydroxyalkoxy group having 1 to 6 carbon atoms and an alkyl group having 1 to 6 carbon atoms, specifically Examples include hydroxymethoxyethyl group, hydroxyethoxyethyl group, hydroxypropyloxypropyl group and the like.
  • an alkyl group having 1 to 6 carbon atoms which may be substituted with a hydroxyl group and/or an alkoxy group having 1 to 2 carbon atoms is preferable, and a hydroxyl group and/or a carbon number
  • An alkyl group having 1 to 4 carbon atoms which may be substituted by an alkoxy group having 1 to 2 carbon atoms is preferred, and an alkyl group having 1 to 2 carbon atoms which may be substituted by a hydroxyl group and/or an alkoxy group having 1 to 2 carbon atoms is preferred. Even more preferred.
  • R 3 in the formula (I) is (1) a straight chain having 1 to 10 carbon atoms or It represents a branched alkyl group, and is preferably a group in which at least one carbon atom of the alkyl group is substituted with -O-.
  • R 3 include formula (III): [Wherein, r and s each independently represent a number of 2 or 3, X represents a hydrogen atom or a methyl group, and at least one hydrogen atom in formula (III) is a hydroxyl group or a C 1 or 2 and/or an alkoxy group having 1 to 6 carbon atoms]. At least one hydrogen atom of the group may be substituted with a halogen atom.
  • Such groups preferably include a trifluoromethoxyethyl group, a trifluoromethoxypropyl group, and the like.
  • the linear or branched chain having 1 to 10 carbon atoms optionally substituted with a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, and/or an alkoxy group having 1 to 6 carbon atoms, etc., as described above.
  • a branched alkyl group may be a group having at least one hydrogen atom substituted with a halogen atom.
  • R 3 in the above formula (II) represents (2) an alicyclic hydrocarbon group having 3 to 12 carbon atoms including an alicyclic structure having 3 to 6 carbon atoms, an alicyclic ring having 3 to 6 carbon atoms
  • Formula structures include, for example, cyclohexane. At least one carbon atom of the alicyclic hydrocarbon group having 3 to 12 carbon atoms may be substituted with -O-, -N- or -S-, and the alicyclic hydrocarbon group having 3 to 12 carbon atoms At least one hydrogen atom of the group may be replaced by a hydroxyl group, an alkyl group having 1 or 2 carbon atoms and/or an alkoxy group having 1 to 6 carbon atoms.
  • the alicyclic hydrocarbon group having 3 to 12 carbon atoms containing an alicyclic structure having 3 to 6 carbon atoms in which at least one carbon atom is substituted with an oxygen atom includes an alicyclic hydrocarbon group having 3 carbon atoms, epoxy group in which one carbon atom of a cyclic hydrocarbon group is substituted with an oxygen atom, oxetanyl ring in which one carbon atom of an alicyclic hydrocarbon group having 4 carbon atoms is substituted with an oxygen atom, alicyclic hydrocarbon groups having 5 carbon atoms, Examples include a dioxolane ring in which two carbon atoms of a cyclic hydrocarbon group are substituted with oxygen atoms, and a dioxane ring in which two carbon atoms of an alicyclic hydrocarbon group having 6 carbon atoms are substituted with oxygen atoms.
  • Hydrogen atoms on these rings may be substituted with alkyl groups having 1 or 2 carbon atoms.
  • alkyl groups having 1 or 2 carbon atoms include 3-ethyl-3-oxetanylmethyl (meth)acrylate, 2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate and the like.
  • alicyclic structures having 3 to 6 carbon atoms optionally substituted with a hydroxyl group, an alkyl group having 1 or 2 carbon atoms, and/or an alkoxy group having 1 to 6 carbon atoms, etc.
  • the alicyclic hydrocarbon group having 3 to 12 carbon atoms may be a group having at least one hydrogen atom substituted with a halogen atom. When R 3 is such a group, it is easy to improve the heat resistance of the organic piezoelectric film.
  • R 3 in the above formula (II) may represent (3) a phenyl group.
  • At least one hydrogen atom on the phenyl ring of the phenyl group may be substituted with a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, and/or an alkoxy group having 1 to 6 carbon atoms.
  • At least one hydrogen atom on the phenyl ring, particularly the hydrogen atom at the para-position is substituted with an alkyl group having 1 to 4 carbon atoms (preferably 1 or 2), and the hydrogen atom of the alkyl group having 1 to 4 carbon atoms is A group substituted with a halogen atom is preferable from the viewpoint of easily improving the heat resistance of the organic piezoelectric film.
  • the above-described phenyl group optionally having at least one hydrogen atom on the phenyl ring optionally substituted with a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, and/or an alkoxy group having 1 to 6 carbon atoms, etc. may be a group in which at least one hydrogen atom is substituted with a halogen atom.
  • R 3 is such a group, it is easy to improve the heat resistance of the organic piezoelectric film.
  • R 3 in the above formula (II) represents (4) a phenylalkylene group containing an alkylene group having 1 to 4 carbon atoms, at least one carbon atom of the alkylene group is -O-, -N- or - may be substituted with S—, or at least one hydrogen atom on the phenyl ring is substituted with a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and/or a cyano group; may have been
  • the phenylalkylene group in which at least one carbon atom of the alkylene group is substituted with -O- has formula (IV): [p and q are each independently 2 or 3] and at least one hydrogen atom of the alkylene portion and phenyl ring portion of the group is a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and/or a cyano group A group substituted with is mentioned. At least one hydrogen atom contained in the above group may be substituted with a halogen atom. When R 3 is the above group, it is easy to improve the heat resistance of the organic piezoelectric film.
  • At least one hydrogen atom on the alkylene group described above may optionally be substituted with a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, and/or an alkoxy group having 1 to 6 carbon atoms, etc., and /or a phenylalkylene group in which at least one hydrogen atom on the phenyl ring may be substituted with a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and/or a cyano group may be a group in which at least one hydrogen atom is substituted with a halogen atom.
  • R 3 is such a group, it is easy to improve the heat resistance of the organic piezoelectric film.
  • (meth)acrylic monomers satisfying the above formula (II) include 3,3,3-trifluoropropyl (meth)acrylate, 3,3,3-trichloropropyl (meth)acrylate, methyl (meth) Acrylates, 4,4,4-trifluorobutyl (meth)acrylate, 4,4,4-trichlorobutyl (meth)acrylate, 2,2-difluoroethyl (meth)acrylate, 2,2-dichloroethyl (meth)acrylate , 4-(trifluoromethyl)cyclohexyl (meth)acrylate, 4-(trichloromethyl)cyclohexyl (meth)acrylate and the like.
  • the (meth)acrylic polymer optionally contained in the organic piezoelectric film of the present invention may have only structural units derived from one type of (meth)acrylic monomer represented by formula (II) above. However, it may have structural units derived from two or more (meth)acrylic monomers represented by the above formula (II).
  • the (meth)acrylic polymer optionally contained in the organic piezoelectric film of the present invention may contain structural units derived from at least one other monomer as long as the properties of the organic piezoelectric film of the present invention are not impaired. good.
  • the (meth)acrylic polymer optionally contained in the organic piezoelectric film of the present invention may be a homopolymer of the (meth)acrylic monomer represented by formula (II) above, or may be a homopolymer of the (meth)acrylic monomer represented by formula (II) above. It may be a copolymer of two or more (meth)acrylic monomers represented by (II), or at least one (meth)acrylic monomer represented by the above formula (II) and at least It may be a copolymer with one other monomer.
  • Other monomers copolymerizable with the (meth)acrylic monomer represented by the formula (II) include, for example, the acrylic monomer represented by the formula (I), the carboxyl group-containing monomer, the formula (I) Or carboxylic acid alkyl ester-based monomers other than (meth)acrylic monomers that give structural units represented by formula (II), amide group-containing monomers, aryl group-containing monomers, styrene-based monomers, nitrogen atom-containing monomers, fatty acid vinyl esters system monomers, betaine monomers, and the like. Specific examples of each monomer include those described in formula (I) above.
  • carboxylic acid alkyl ester monomers other than (meth)acrylic monomers that provide the structural unit represented by formula (II) include, for example, dodecyl (meth)acrylate, stearyl (meth)acrylate, and other alkyl group carbon atoms
  • Examples include alkyl acrylates having 11 to 20 carbon atoms and alkyl itaconic acid esters having alkyl groups having 1 to 4 carbon atoms such as methyl itaconate and ethyl itaconate.
  • the lower limit of the proportion of the piezoelectric polymer in the organic piezoelectric film of the present invention is not particularly limited, but is preferably 25% by mass or more, more preferably 30% by mass or more, and still more preferably 35% by mass based on the entire organic piezoelectric film. 50% by mass or more, particularly preferably 70% by mass or more, even more preferably 80% by mass or more, extremely preferably 90% by mass or more, and extremely more preferably 95% by mass or more.
  • the upper limit of the proportion of the piezoelectric polymer in the organic piezoelectric film of the present invention may be 100% by mass or less based on the entire organic piezoelectric film, for example, 95% by mass or less, 90% by mass or less, 80% by mass or less.
  • the ratio of the piezoelectric polymer in the organic piezoelectric film of the present invention may be obtained from the ratio of the raw material polymer in the raw material film, which will be described later, assuming that all of the raw material polymer is the piezoelectric polymer.
  • the shape of the organic piezoelectric film of the present invention is not particularly limited, and can be any desired shape according to the application and purpose.
  • an example of the upper limit of the thickness can be 400 ⁇ m or less, and further can be 200 ⁇ m or less, 100 ⁇ m or less, or 50 ⁇ m or less.
  • the thickness can be 0.1 ⁇ m or more, and further can be 1 ⁇ m or more, 10 ⁇ m or more, or 20 ⁇ m or more.
  • the thickness of the organic piezoelectric film of the present invention is the arithmetic mean value of each thickness measured at 9 points on the film selected to eliminate arbitrariness.
  • selecting 9 points by eliminating arbitrariness on the film can be performed by selecting 9 points so that each is separated by 15 mm or more in a range of 50 mm in length and 50 mm in width, for example.
  • Arbitrariness means that the thickness variation is intended to be small.
  • the organic piezoelectric film of the present invention is a stretched or unstretched film, and preferably has a stretch ratio of 800% or less, more preferably 600% or less, even more preferably 400% or less, and particularly preferably 0% or less (unstretched film). ).
  • the stretch ratio refers to a value obtained by dividing the length of the film in the stretching direction after stretching by the length of the film before stretching in the direction corresponding to the lengthwise direction of the film after stretching.
  • the stretching treatment may be performed on the organic piezoelectric film, or may be performed on the raw material film described later. Therefore, the stretched film can be a raw material film or an organic piezoelectric film.
  • the organic piezoelectric film of the present invention preferably has high thickness uniformity from the viewpoint of further reducing in-plane variations in piezoelectricity.
  • the organic piezoelectric film of the present invention has a thickness variation coefficient of 10% or less, 5% or less, or 1% or less.
  • the thickness variation coefficient is the ratio of the standard deviation to the arithmetic mean of the thickness of the film described above.
  • the organic piezoelectric film of the present invention has particularly small deflection
  • the organic piezoelectric film of the present invention and the laminate of the present invention using the film can reduce deflection and have high smoothness.
  • deflection of an organic piezoelectric film is measured as curl.
  • an organic piezoelectric film with a width of 50 mm and a length of 50 mm was fixed on a metal plate by attaching a tape with a width of 25 mm along a line passing through the position and center of the width of 25 mm, and heated at 80 ° C. for 30 minutes. Later, it is measured by a method of measuring the lifted height of both ends of the film from the metal plate with a vernier caliper.
  • the curl of the organic piezoelectric film of the present invention is preferably 1 mm or less, more preferably 0.5 mm or less, and even more preferably 0.1 mm or less from the viewpoint of easily improving the smoothness and uniformity of the organic piezoelectric film.
  • the organic piezoelectric film of the present invention includes, for example, various piezoelectric elements such as piezoelectric sensors, transducers, and infrared pyroelectric sensors, large-area touch panels capable of detecting touch pressure, large-area pressure sensors, haptic devices, vibration It is particularly suitable as a component for devices such as power generators and large-area flat speakers.
  • various piezoelectric elements such as piezoelectric sensors, transducers, and infrared pyroelectric sensors, large-area touch panels capable of detecting touch pressure, large-area pressure sensors, haptic devices, vibration It is particularly suitable as a component for devices such as power generators and large-area flat speakers.
  • the laminate of the present invention is a laminate including the above-described organic piezoelectric film of the present invention and an electrode connected to at least a portion of one surface of the organic piezoelectric film. Since the laminate of the present invention includes the organic piezoelectric film of the present invention having small in-plane variations in piezoelectricity and a reduced number of defects, it is easy to form a laminate having a large area. Examples of such laminates include the above-described sensors and equipment members. Since the organic piezoelectric film provided in the laminate of the present invention is the same as that described above, the electrodes provided in the laminate of the present invention will be mainly described below.
  • the electrode provided in the laminate of the present invention is connected to at least part of one surface of the organic piezoelectric film.
  • the electrodes are usually composed of a pair of electrodes including an anode and a cathode, and at least one of the anode and the cathode should be connected to at least one surface of the organic piezoelectric film.
  • the laminate of the present invention may have a form comprising an anode connected to at least a portion of one surface of the organic piezoelectric film and a cathode connected to at least a portion of the other surface of the organic piezoelectric film.
  • the electrodes and the organic piezoelectric film may be directly connected, or may be indirectly connected via a member or the like as long as the electrical conductivity can be secured.
  • it may be connected to at least a part of one surface (the other surface) of the organic piezoelectric film, or may be connected to the entire surface.
  • the electrode is formed so as to cover the entire surface of one surface (the other surface) of the organic piezoelectric film.
  • members such as wiring are connected to the electrodes depending on the application for which the laminate is used.
  • the material of the electrode is not particularly limited as long as it has conductivity, and known materials can be used. Examples include metals such as gold, silver, copper and aluminum, and metal oxides such as ITO (indium tin oxide).
  • the shape of the electrode is not particularly limited, and can be designed according to the use of the laminate. An example of the shape of the electrode is a shape that covers at least one of one side and the other side of the organic piezoelectric film.
  • the method for producing the organic piezoelectric film of the present invention is not particularly limited as long as an organic piezoelectric film that satisfies the above characteristics can be obtained.
  • the method includes a polymer that has piezoelectricity when subjected to a polarization treatment. It is preferable to manufacture by a manufacturing method including a step of covering one surface of the raw material film with a cover film satisfying specific conditions and applying a voltage from above the cover film to perform a polarization treatment.
  • a manufacturing method including a step of covering one surface of the raw material film with a cover film satisfying specific conditions and applying a voltage from above the cover film to perform a polarization treatment.
  • the present invention also provides a method for producing the above organic piezoelectric film.
  • the reason why an organic piezoelectric film having small in-plane variations in piezoelectricity and a reduced number of defects can be easily produced by the method for producing an organic piezoelectric film of the present invention is presumed as follows. It does not limit the invention in any way.
  • the reason why the in-plane variation occurs in the piezoelectricity is thought to be that the voltage applied during the polarization treatment is non-uniform in the plane of the raw material film. Specifically, in the non-contact polarization treatment in which the polarization treatment is performed without contact between the applied electrode and the raw material film, the state of the atmosphere between the applied electrode and the raw material film, that is, the temperature, humidity, and density of the atmosphere , etc. are not necessarily uniform.
  • the voltage applied from the application electrode temporarily charges the cover film directly under it, spreads uniformly over a certain extent in the surface direction, and then charges the material film. is applied to It is considered that this is because an effect equivalent to dielectric barrier discharge (silent discharge) works.
  • an organic piezoelectric film of the present invention it is possible to uniformly apply a voltage to a raw material film in the plane direction to some extent, and to locally apply a voltage high enough to cause dielectric breakdown. can be prevented. It is believed that this makes it possible to efficiently manufacture an organic piezoelectric film with small in-plane variations in piezoelectricity and a reduced number of defects.
  • the application electrode when a needle-shaped electrode having a large number of discharge needles is used as the application electrode, even in the portion covered with the application electrode, the voltage applied directly below the tip of each discharge needle and its peripheral portion is large. tend to differ. Similarly, in the raw material film, a portion where a high voltage enough to cause dielectric breakdown is locally applied becomes a defect. likely to occur.
  • the voltage applied from the tip of each needle-like electrode temporarily charges the cover film immediately below it, and spreads it to some extent in the plane direction. Since the voltage is applied to the raw material film after it spreads uniformly to some extent, it is thought that an organic piezoelectric film with small in-plane variations in piezoelectricity and a reduced number of defects can be efficiently manufactured.
  • the applied voltage temporarily charges the cover film and spreads to some extent in the surface direction to reach an average value. Since the voltage is applied, it is presumed that the voltage can be applied uniformly to some extent in the surface direction of the raw material film. It is believed that this makes it possible to efficiently produce an organic piezoelectric film with small in-plane variations in piezoelectricity.
  • the method for producing an organic piezoelectric film of the present invention includes a coating step and a polarization step. Each step will be described below.
  • the coating step at least part of one side of the raw material film containing a polymer having piezoelectricity by being polarized is covered with the formula: ln(C ⁇ ) ⁇ 17 [wherein C is capacitance (pF) and ⁇ is conductivity (S/m)] It is a step of covering with a cover film that satisfies At least part of the raw material film is covered with the cover film in the covering step.
  • the coating step is performed on a portion of the material film to be imparted with piezoelectric properties, for example, on at least a portion of one side of the material film, preferably on the entire surface.
  • known methods and devices for coating the first film on the second film can be employed.
  • a raw material film is a film containing the raw material polymer described above.
  • the type of raw material polymer is not particularly limited, and known materials such as the raw material polymers described above can be used.
  • Raw material films include films that exhibit no piezoelectric properties at all, films that have piezoelectric properties below desired piezoelectric properties, and films that have been crystallized.
  • a commercially available raw material film may be used, or it may be produced by a method described later or a known method such as inflation molding.
  • the cover film is a film that covers and protects one surface of the raw material film, and satisfies the formula: ln(C ⁇ ) ⁇ 17 (hereinafter simply referred to as satisfying the formula; It is preferable that the cover film that satisfies the formula is used, except when where C is the capacitance (pF) and ⁇ is the conductivity (S/m).
  • the ln(C ⁇ ) value of the cover film is preferably greater than ⁇ 17, more preferably ⁇ 15 or more, and even more preferably ⁇ 13 or more from the viewpoint of easily obtaining an organic piezoelectric film with small in-plane variation and few defects. .
  • the upper limit of the value of ln(C ⁇ ) of the cover film is preferably -8 or less, more preferably -10 or less, and still more preferably -12 or less from the viewpoint of obtaining an organic piezoelectric film with few defects.
  • the structure of the cover film may be a one-layer film formed from a single material, a one-layer film formed by mixing a plurality of materials, or a multi-layer film in which these materials are laminated.
  • the material of the cover film may be any material as long as it satisfies the formula, but a material containing at least one of cellulose and silicon is preferable from the viewpoint of easily obtaining a cover film that satisfies the formula.
  • the shape of the cover film may be any shape as long as it can cover the portion to which the raw material film is to be imparted with piezoelectricity.
  • the thickness of the cover film is not particularly limited, it is preferably 10 ⁇ m to 1000 ⁇ m, more preferably 300 ⁇ m to 500 ⁇ m from the viewpoint of efficient polarization treatment.
  • the cover film is fixed in close contact with the raw material film by having a force due to static electricity or an adhesive surface.
  • the capacitance C of the cover film conforms to JIS C 2138: 2007 and is measured using an impedance analyzer (manufactured by Solartron Analytical, product name: Dielectric interface: 1296, Impedance/gain-phase analyzer: SI1260, or equivalent). and a room-temperature sample holder (Solartron Analytical product name: 12962A, or equivalent), and under the following conditions. Measurement section: circle with a diameter of 2 cm, measurement frequency: 1 MHz to 1 Hz, voltage: AC 1 V, integration: 1 cyc
  • the capacitance C (pF) is preferably 1 or more and 500 or less, more preferably 20 or more and 300 or less, and even more preferably 30 or more and 100 or less, on the premise that the above formula is satisfied.
  • the conductivity ⁇ of the cover film conforms to JIS C 2138: 2007, and can be obtained by measuring ⁇ ′′ under the following conditions with the impedance analyzer described above and applying the measurement results to the following equation.
  • the conductivity ⁇ (S/m) is preferably 1.0 ⁇ 10 -11 or more and 1.0 ⁇ 10 -7 or less, and 5.0 ⁇ 10 ⁇ 11 or more and 7.5 ⁇ 10 ⁇ 8 or less is more preferable, and 1.0 ⁇ 10 ⁇ 10 or more and 5.0 ⁇ 10 ⁇ 8 or less is more preferable.
  • the raw material film is covered with a cover film such that the application electrode and the cover film are opposed to each other and the ground electrode and the other surface of the raw material film are connected to a polarizing device having an application electrode and a ground electrode.
  • a polarizing device having an application electrode and a ground electrode.
  • the polarization device used in the polarization process is a device that can apply voltage to the raw material film.
  • the polarizer includes an application electrode and a ground electrode, and an electric field is generated between the application electrode and the ground electrode to polarize the raw material film.
  • the application electrode is an electrode on the high potential side, and electron emission and ion generation are performed by applying a voltage, and an electric field is generated.
  • the ground electrode is an electrode on the reference potential side, and is an electrode that equalizes the applied voltage.
  • a polarization treatment method and a polarization device for carrying out the polarization treatment a known polarization treatment method and polarization device can be used.
  • a commercially available polarizer can be used for the polarization treatment, for example, a non-contact polarizer in which the application electrode does not come into contact with the raw material film by providing a space between the application electrode and the cover film to perform the polarization treatment. , and a contact-type polarizer in which an application electrode is brought into contact with the raw material film to perform the polarizing treatment.
  • a needle-like electrode having a large number of discharge needles, a linear electrode, or a lattice-like electrode can be used as the application electrode provided in the non-contact polarization device.
  • the distance between the applying electrode and the cover film is not particularly limited, but from the viewpoint of efficient polarization treatment, it is preferably 1 mm or more and 50 mm or less, and 5 mm or more and 30 mm or less. is more preferred.
  • the raw material film covered with the cover film is placed so that the application electrode and the cover film face each other, and the ground electrode and the other surface of the raw material film are connected.
  • the application electrode and the cover film are 90% or more, preferably 95% or more, more preferably 99% or more of the application electrode and the cover film, assuming that all the locations to be polarized in the raw material film are covered with the cover film, Particularly preferably, they are installed so that 100% of them face each other.
  • the poling process is carried out by applying a force to the raw material film that resists the shrinkage stress generated by the polarization treatment (hereinafter referred to as a force that resists the shrinkage stress).
  • a force that resists the shrinkage stress is applied to at least one of the raw material film, the cover film, and the base material to directly apply the force to the raw material film.
  • a method of indirectly imparting tension and a method of imparting tension by bringing the raw material film into close contact with a base material having a predetermined rigidity in the fixing step described later.
  • the poling process can be performed while the raw material film is fixed to the substrate.
  • the manufacturing method of the organic piezoelectric film of the present invention can include a fixing step of fixing the raw material film to the substrate. By performing the fixing step, it is possible to efficiently produce an organic piezoelectric film with few wrinkles.
  • the fixing step may be performed before the polarization step, may be performed before the coating step, may be performed after the coating step, or may be performed simultaneously with the coating step.
  • the base material is a member to which the raw material film is fixed.
  • an organic piezoelectric film with less wrinkles can be efficiently produced by performing the poling process in a state where the raw material film is fixed to a base material having a predetermined rigidity.
  • the substrate may be a cover film, or may be a member different from the cover film.
  • the other surface (the surface not covered with the cover film) of the raw material film and the substrate are fixed. At least a part of the other surface of the raw material film needs to be fixed to the base material, and the raw material film is preferably fixed by being in close contact with the base material.
  • the raw material film is fixed to the extent that it is restricted from moving relative to the substrate, more preferably to the extent that shrinkage of the raw material film in the above-described polarization process can be restricted.
  • the material of the base material can have rigidity that resists the shrinkage stress.
  • the base material may have conductivity, and in this case, the base material can be used as a ground electrode of a polarizer or can be connected to a ground electrode, resulting in excellent productivity.
  • the arithmetic mean surface roughness (Ra) of the substrate is preferably 1 ⁇ m or less.
  • the base material include metal materials such as stainless steel (SUS), aluminum and copper, and resin materials such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).
  • SUS stainless steel
  • resin materials such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).
  • PET polyethylene terephthalate
  • PEN polyethylene naphthalate
  • the metal material described above or a composite material of a metal material and a resin or the like may be used.
  • the shape of the base material is not particularly limited and can be selected according to the manufacturing method, and examples thereof include shapes such as sheet and flat plate.
  • the fixing step a known method/apparatus for coating the first film on the second film can be used.
  • the fixing step can be carried out by using a laminator or a press, laminating by hand, or the like.
  • the aspect which has a coating process and a raw material film formation process is mentioned.
  • the coating step is performed on the raw material film obtained in the raw film forming step.
  • the physical properties other than the piezoelectric properties such as transparency are less likely to change than the method of applying tension to the raw material film, etc., to resist shrinkage stress.
  • the physical properties other than the piezoelectric properties are less likely to change before and after the polarization treatment.
  • the coating process is a process of forming a coating film by coating a substrate with a coating liquid containing an organic material that is polarized and has piezoelectricity.
  • the coating liquid is a solution for producing the raw material film.
  • the coating liquid contains raw materials for the organic piezoelectric film, such as the raw material polymer, and monomers and oligomers that become the raw material polymer when polymerized. agents, other materials exemplified in the organic piezoelectric films described above.
  • a coating liquid typically contains a raw material polymer and a solvent (especially an organic solvent).
  • a known method of applying a coating liquid to a substrate and an apparatus capable of performing this method can be used. Examples of equipment that can be used in the coating step include spin coaters, bar coaters, die coaters, and the like.
  • the raw material film forming process is the process of obtaining the raw material film from the coating film.
  • the coating film is a film obtained by curing the above coating liquid.
  • the coating film does not have to be a completely cured coating solution, and when used as it is as a raw material film, the coating film is subjected to other treatments to the extent that it can be covered with a cover film described later.
  • the raw material film When the raw material film is produced by the method, it may be cured to the extent required for the treatment. Examples of treatments performed in the raw material film forming process include heat treatment of the coating film, irradiation of the coating film with light such as ultraviolet rays, drying of the coating film, and combinations thereof, etc., depending on the type of the coating film. is mentioned.
  • the coating film itself may be the raw material film.
  • the raw material film may be subjected to other treatments before the poling process, an example of which is a crystallization process for crystallizing the raw material film.
  • a crystallization process for crystallizing the raw material film By including the crystallization step, an organic piezoelectric film with high piezoelectric properties can be efficiently produced.
  • a known crystallization method and crystallization apparatus can be used, and typically a heating apparatus capable of heating the raw material film at an arbitrary temperature is used.
  • the raw material film includes a crystallized film. is preferably carried out during the polarization treatment after crystallization.
  • the coating step is performed on the raw film obtained in the raw film forming step. Specifically, the coating step is performed on the exposed surface (the surface not in contact with the substrate) of the raw material film obtained in the raw material film forming step.
  • the transport direction (the direction from the left side of the drawing to the right side; also referred to as the MD direction) is the length direction, the thickness direction, and the transport direction.
  • the direction perpendicular to (the depth direction of the paper surface) is defined as the width direction.
  • Embodiment 1 In Embodiment 1, an embodiment in which an organic piezoelectric film is manufactured by a roll-to-roll method in the method for manufacturing an organic piezoelectric film of the present invention will be described.
  • the manufacturing apparatus 1A used in this embodiment includes a conveying device 2A and a polarizing device 3A.
  • the production apparatus 1A is an apparatus for continuously producing an organic piezoelectric film 9A from a raw material film 7A by a roll-to-roll method.
  • the conveying device 2A includes a raw material film delivery roll 21A arranged at the upstream end in the conveying direction (the left side of the drawing; hereinafter simply referred to as the upstream side; the same applies to the downstream side, which is the right side of the drawing); A cover film delivery roll 22A arranged at the upstream end, a set of pressure rollers 23A and 24A, a winding roll 25A arranged at the downstream end, a guide roller 26A, and a driving device (not shown).
  • a raw material film delivery roll 21A arranged at the upstream end in the conveying direction (the left side of the drawing; hereinafter simply referred to as the upstream side; the same applies to the downstream side, which is the right side of the drawing);
  • a cover film delivery roll 22A arranged at the upstream end, a set of pressure rollers 23A and 24A, a winding roll 25A arranged at the downstream end, a guide roller 26A, and a driving device (not shown).
  • the raw material film 7A is wound around the raw material film feed roll 21A, and is configured to be able to feed the raw material film 7A with respect to a pair of pressing rollers 23A and 24A.
  • the cover film 8A that satisfies the above-described formula is wound around the cover film delivery roll 22A, and the cover film 8A is configured to be delivered to a pair of pressing rollers 23A and 24A.
  • a pair of pressing rollers 23A, 24A are arranged downstream of both feed rolls 21A, 22A and upstream of an application electrode 31A of a polarization device 3A, which will be described later.
  • a gap (hereinafter referred to as , simply referred to as a gap), the cover film 8A is pressed against one surface of the raw material film 7A, and the raw material film 7A is covered with the cover film 8A.
  • the size of the gap formed by the pair of pressing rollers 23A and 24A is less than the sum of the thickness of the raw material film 7A and the thickness of the cover film 8A from the viewpoint of covering the raw material film 7A with the cover film 8A.
  • the size of the gap formed by the pair of pressing rollers 23A and 24A is preferably equal to the thickness of the raw material film 7A and the thickness of the cover film 8A. less than the sum of The pair of pressing rollers 23A and 24A of this embodiment are configured so that the size of the gap can be adjusted.
  • the take-up roll 25A is arranged downstream of both feed rolls 21A and 22A and downstream of the application electrode 31A of the polarization device 3A.
  • the take-up roll 25A is wound with a laminated film 10A having a raw material film 7A (that is, an organic piezoelectric film 9A) that has been polarized by the polarization device 3A and a cover film 8A coated thereon.
  • the laminated film 10A transported from 3A can be wound up.
  • the guide roller 26A is arranged downstream of the applying electrode 31A of the polarizer 3A and upstream of the winding roll 25A, and is in contact with the other surface of the organic piezoelectric film 9A, thereby winding the laminated film 10A to the winding roll. 25A.
  • the guide roller 26A of this embodiment also serves as the ground electrode 32A. Therefore, the guide roller 26A is made of a conductive material such as rubber mixed with metal or conductive filler.
  • the polarizing device 3A is a device that polarizes the raw material film 7A.
  • the polarization device 3A includes an application electrode 31A, a ground electrode 32A, a power source section 33A, and wirings 34A and 35A.
  • the polarizing device 3A of this embodiment is a non-contact polarizing device that polarizes the material film 7A by generating ions by corona discharge from the applying electrode 31A using a voltage supplied from the power source 33A through the wiring 34A. .
  • the application electrode 31A is installed so as to face the cover film 8A. Further, the application electrode 31A is formed so as to cover the entire surface of the material film 8A in the width direction.
  • the application electrode 31A is connected to the power source section 33A by a wiring 34A.
  • the ground electrode 32A according to this embodiment is the guide roller 26A described above.
  • the ground electrode 32A is grounded by a wiring 35A.
  • the positional relationship of the guide roller 26A and the take-up roll 25A be set so that the film 7A and the film 8A are tensioned to the extent that the film 7A and 8A do not change their lengthwise dimensions.
  • the raw material film 7A and the cover film 8A are conveyed by driving a driving device (not shown).
  • the raw material film 7A transported into the gap formed by the pair of pressing rollers 23A and 24A is pressed by the pair of pressing rollers 23A and 24A together with the cover film 8A also transported into the gap, so that one surface of the raw material film 7A is covered. Covered with film 8A (covering step).
  • the set of pressure rollers 23A and 24A press the cover film 8A against the raw material film 7A, A cover film 8A is fixed in close contact with one surface of the raw material film 7A.
  • the raw material film 7A covered with the cover film 8A is conveyed to the area where the application electrodes 31A are provided.
  • the application electrode 31A is installed so as to face the cover film 8A, and the ground electrode 32A (guide roller 26A) is arranged so as to connect (contact) with the other surface of the raw material film 7A. .
  • the polarization device 3A By driving the polarization device 3A in this state, an electric field is generated between the application electrode 31A and the ground electrode 32A, and the raw material film 7A covered with the cover film 8A is polarized (polarization process).
  • the organic piezoelectric film 9A manufactured by the above polarization treatment is conveyed as a laminated film 10A coated on one side with the cover film 8A and wound up on the winding roll 25A.
  • the method of manufacturing the organic piezoelectric film of this embodiment has, for example, the following advantageous effects.
  • the organic piezoelectric film of the present invention can be continuously produced, and the productivity is excellent.
  • ⁇ Excellent manufacturability because there is no need to prepare a base material separately.
  • ⁇ Since the poling process is performed in a state in which a constant tension is applied to the raw material film in the length direction, the occurrence of wrinkles is suppressed.
  • Embodiment 2 In Embodiment 2, an embodiment including one aspect of the fixing step in the method for producing an organic piezoelectric film of the present invention will be described. The description of the parts common to the first embodiment will be omitted, and the differences and main features will be mainly described. The same applies to other embodiments described later.
  • the manufacturing apparatus 1B used in this embodiment includes a conveying device 2B and a polarizing device 3B.
  • the conveying device 2B includes a raw material film delivery roll 21B arranged at the upstream end, a cover film delivery roll 22B arranged at the upstream end, and a cover film delivery roll 22B arranged at the upstream end. It includes a base material delivery roll 27B, a pair of pressure rollers 23B and 24B, a winding roll 25B arranged at the downstream end, a guide roller 26B, and a driving device (not shown).
  • the base material 6B is wound around the base material delivery roll 27B, and the base material 6B is configured to be able to be delivered to the pair of pressing rollers 23B and 24B.
  • the base material 6B of this embodiment is a flexible base material that can be wound around the base material delivery roll 27B, and specific materials thereof include SUS, iron, aluminum, and the like.
  • a pair of pressing rollers 23B, 24B are arranged downstream of the three delivery rolls 21B, 22B, 27B and upstream of the applying electrode 31B of the polarization device 3B.
  • the cover film 8B drawn out from the cover film drawing-out roll 22B is centered on the raw material film 7B drawn out from the raw film drawing-out roll 21B. is supplied to one side of the raw material film 7B, and the base material 6B drawn out from the base material drawing roll 27B is supplied to the other side of the raw material film 7B.
  • the size of the gap formed by the pair of pressing rollers 23B and 24B is equal to or less than the sum of the thickness of the raw material film 7B, the thickness of the cover film 8B, and the thickness of the base material 6B. Yes, preferably less than the sum of the thickness of the raw material film 7B, the thickness of the cover film 8B, and the thickness of the substrate 6B.
  • the winding roll 25B is arranged downstream of the application electrode 31B of the polarization device 3B.
  • the take-up roll 25B includes a raw material film 7B (that is, an organic piezoelectric film 9B) polarized by the polarization device 3B, a cover film 8B coated on one side, and a base material 6B fixed on the other side.
  • the laminated film 10B including the organic piezoelectric film 9B conveyed from the polarization device 3B is wound up.
  • the position of each member of the driving device 2B is adjusted so that the material film 7B, the cover film 8B, and the base material 6B do not slack.
  • the material film 7B is fixed in close contact with the base material 6B, thereby imparting rigidity to the material film 7B against shrinkage during the polarization process.
  • the positional relationship and the like of the guide roller 26B and the take-up roll 25B may be set so that at least a portion of the tension is applied.
  • the material film 7B, the cover film 8B, and the base material 6B are conveyed by driving a driving device (not shown).
  • the pair of pressing rollers 23B and 24B press the cover film 8B against one surface of the raw material film 7B to cover the one surface with the cover film 8B (covering step).
  • the base material 6B which has also been conveyed into the gap, is pressed by the pair of pressure rollers 23B and 24B, and the base material 6B is fixed to the other surface of the raw material film 7B. (fixing step).
  • the raw material film 7B is pressed against the cover film 8B by the set of pressure rollers 23B and 24B, so that the cover film 8B is tightly fixed to one surface of the raw material film 7B.
  • the raw material film 7B fixed to the base material 6B and covered with the cover film 8B is conveyed to the area where the application electrodes 31B are provided.
  • the application electrode 31B is installed so as to face the cover film 8B, and the ground electrode 32B (guide roller 26B) is arranged so as to connect (contact) the other surface of the raw material film 7B. .
  • the polarization device 3B By driving the polarization device 3B in this state, an electric field is generated between the application electrode 31B and the ground electrode 32B, and the raw material film 7B fixed to the base material 6B and covered with the cover film 8B is polarized. processed (polarization process).
  • the organic piezoelectric film 9B manufactured by the above polarization treatment is transported as a laminated film 10B with one surface covered with the cover film 8B and the other surface fixed with the substrate 6B, and wound up on the winding roll 25B.
  • the method of manufacturing the organic piezoelectric film of this embodiment has, for example, the following advantageous effects.
  • the organic piezoelectric film of the present invention can be continuously produced, and the productivity is excellent.
  • ⁇ By using the base material it is possible to efficiently produce an organic piezoelectric film with few wrinkles.
  • ⁇ It is not necessary to apply excessive tension to the raw material film and the cover film because the main part of the force against the shrinkage of the raw material film in the polarization process is given by the adhesion with the highly rigid base material. For this reason, it is possible to suppress changes in physical properties (transparency, Young's modulus, etc.) due to the unstretched raw material film being stretched.
  • Embodiment 3 In Embodiment 3, an embodiment including a coating step and a raw material film forming step will be described as another aspect of the fixing step in the method for producing an organic piezoelectric film of the present invention.
  • the manufacturing apparatus 1C used in this embodiment includes a conveying apparatus 2C, a polarization apparatus 3C, and a raw material film manufacturing apparatus 4C.
  • the conveying device 2C includes a base material delivery roll 27C arranged at the upstream end, a cover film delivery roll 22C arranged at the upstream end, and a pair of pressure rollers 23C and 24C. , a winding roll 25C disposed at the downstream end, a guide roller 26C, and a driving device (not shown).
  • the raw material film manufacturing device 4C is arranged between the base material delivery roll 27C and the cover film delivery roll 22C, and includes a discharge device 41C, a guide 43C, and a dryer 44C.
  • the discharge device 41C supplies the stored coating liquid 42C to one surface of the substrate 6C.
  • the guide 43C evenly spreads the coating liquid 42C discharged onto the one surface of the substrate 6C over the entire surface of the substrate 6C.
  • the guide 43C is formed so that the distance from the one surface of the base material 6C can be adjusted.
  • the dryer 44C dries the spread coating liquid 42C.
  • the cover film 8C and the base material 6C are pulled out from the delivery rolls 22C and 27C, respectively, and fixed to the take-up roll 25C through a gap formed by a pair of pressing rollers 23C and 24C and a guide roller 26C.
  • the cover film 8C covers one surface of the manufactured raw material film 7C, and the gap is large enough so that the cover film 8C is pressed and fixed to one surface of the raw material film 7C to be manufactured. adjust the depth.
  • the position of each member of the driving device 2C is adjusted so that the cover film 8C and the base material 6C do not slack.
  • the cover film 8C and the base material 6C are conveyed by driving a driving device (not shown).
  • a coating liquid 42C is supplied by a discharge device 41C to one surface of the base material 6C fed out from the base material delivery roll 27C, and the coating liquid 42C coated on the base material 6C is applied to the end surface of the guide 43C.
  • the coating is applied to the entire width direction of the one surface of the substrate 6C with a uniform thickness to form the coating film 45C (coating step).
  • the coating film 45C is dried by passing under the dryer 44C, and the raw material film 7C is manufactured (raw material film forming step).
  • the raw material film 7C thus obtained has one surface exposed and the other surface fixed in close contact with one surface of the base material 8C, and is transported to the gap formed by the pair of pressing rollers 23C and 24C.
  • the cover film 8C conveyed into the gap is pressed by the pair of pressing rollers 23C and 24C, so that one surface of the raw material film 7C is covered with the cover film 8C. (coating step). Since subsequent steps are the same as those of the second embodiment, the description is omitted.
  • the method of manufacturing the organic piezoelectric film of this embodiment has the following effects.
  • the organic piezoelectric film of the present invention can be efficiently produced by continuing from the production of the raw material film.
  • the adhesion between the base material and the raw material film is improved, and wrinkles are further suppressed.
  • Embodiment 4 in the method for producing an organic piezoelectric film of the present invention, a mode using a cover film satisfying the formula as a base material and a mode having a crystallization step will be described.
  • the manufacturing apparatus 1D used in this embodiment includes a conveying apparatus 2D, a polarization apparatus 3D, a raw material film manufacturing apparatus 4D, and a crystallization apparatus 5D.
  • the conveying device 2D includes a base material delivery roll 27D arranged at the upstream end, a winding roll 25D arranged at the downstream end, a set of guide rollers 26D1 and 26D2, and a driving device (not shown).
  • the cover film 8D is wound around the base material delivery roll 27D, so the base material delivery roll 27D is also the cover film delivery roll 22D.
  • a guide roller for guiding the organic piezoelectric film 9D to the take-up roll 25D is composed of a pair of guide rollers 26D1 and 26D2.
  • the guide roller 26D1 of this embodiment is also the ground electrode 32D.
  • a gap is formed by a pair of guide rollers 26D1 and 26D2.
  • the application electrode 31D of the polarization device 3D is arranged on the cover film 8D side (lower side in the drawing).
  • the crystallization device 5D is provided downstream of the dryer 44D of the raw material film forming device and upstream of the application electrode 31D.
  • the crystallization device 5D of this embodiment is a heating device.
  • the cover film 8D (base material 6D) is pulled out from the cover film delivery roll 22D and fixed to the take-up roll 25D through a gap formed by a pair of guide rollers 26D1 and 26D2.
  • the size of the gap is adjusted so that the guide roller 26D1 (earth electrode 32D) contacts one surface of the raw material film 7D to be produced.
  • the position of each member of the driving device 2D is adjusted so that the base material 6D does not slack.
  • the substrate 6D is conveyed by driving a driving device (not shown), the coating step is performed by the discharge device 41D, and the raw material film forming step is performed by the dryer 44D, as in the third embodiment.
  • Film 7D is obtained.
  • One surface of the raw material film 7D thus obtained is in a state of being fixed in close contact with the substrate and covered with the cover film, so the raw material film forming step also includes a covering step.
  • Raw material film 7D is heated by passing under crystallizer 5D, and raw material film 7D is crystallized (crystallization step). After that, the raw material film 7D passes over the application electrode 31D to perform the polarization process, and the laminate 10D is wound around the take-up roll 25D through the polarization process in the same manner as in the other embodiments.
  • the method of manufacturing the organic piezoelectric film of this embodiment has the following effects. - Since the cover film is used as the substrate, the organic piezoelectric film of the present invention can be produced with high productivity.
  • Embodiment 5 In Embodiment 5, a method for manufacturing the organic piezoelectric film of the present invention other than roll-to-roll will be described.
  • a coating device (not shown), a non-contact polarization device 3E, a conductive substrate 6E, and a cover film 8E satisfying the formula are used.
  • the base material 6E is prepared (Fig. 5(a)).
  • a coating liquid is applied to the prepared substrate 6E by a coating device (not shown) to form a coating film, which is dried by a dryer (not shown) to form a raw material film 7E (FIG. 5(b)).
  • the raw material film 7E thus obtained is formed from the coating liquid on one surface of the base material 6E, and therefore is fixed in close contact with the base material 6E.
  • the cover film 8E is lightly pressed onto the entire surface of the raw material film 7E and fixed in close contact (coating step) (FIG.
  • the application electrode 31E is arranged at a position facing the cover film 8E, and the base material 6E By connecting the wiring 35E, the substrate 6E is used as the ground electrode 32E, and the polarization process is performed (polarization process) (FIG. 5(d)).
  • the organic piezoelectric film 9E having one surface covered with the cover film 8E and the other surface fixed with the substrate 6E is obtained as the laminated film 10E.
  • the cover film 8E is shaped to cover the entire surface of the raw material film, but the cover film 8E may have a larger area than the raw material film 7E. This is because when the cover film 8E is larger than the raw material film 7E, the cover film 8E is easily removed (peeled off) from the manufactured organic piezoelectric film 9E.
  • the method of manufacturing the organic piezoelectric film of this embodiment has the following effects.
  • ⁇ Piezoelectricity can be imparted in any shape to raw material films of any shape.
  • a material that is not easily wound, such as ITO glass or relatively thick PET film, can be used as the base material. This embodiment is particularly effective when these substrates are used together with the organic piezoelectric film as members or materials without being separated from the organic piezoelectric film.
  • Embodiments 1 to 4 instead of winding the laminate 10 around the take-up roll 25, the cover film 8 and the base material 6 may be removed from the raw film 7 and taken up around the take-up roll 25.
  • a contact-type polarizer may be used as the polarizer.
  • A3 Commercially available polyvinylidene fluoride (manufactured by Aldrich) [Other polymer B]
  • B1 Poly-ethyl acrylate (Poly-EA, weight average molecular weight: 2,200,000, manufactured according to the description in WO2020/012660)
  • B2 Poly-3,3,3-trifluoropropyl methacrylate (Poly-3FPMA, weight average molecular weight: 294,000, manufactured according to the description in WO2020/111106) [Cover film]
  • the piezoelectric constant d 33 of the organic piezoelectric film according to each example and comparative example was measured using a piezoelectric constant measuring device (manufactured by Lead Techno, product name: LPF-02). Specifically, the measurement was performed according to the following procedure. (1) One surface and the other surface of the substrate on which the organic piezoelectric film was formed were sandwiched between needle-like probes. (2) The load applied to the organic piezoelectric film by the probe was set to 1 N, and left still.
  • the piezoelectric constant d 31 of the organic piezoelectric film according to each example and comparative example is measured using a piezoelectric constant measuring device (Piezometer system manufactured by Lead Techno, product name: LPF-03). Specifically, the measurement is performed according to the following procedure. (1) Select 10 locations on the organic piezoelectric film and form gold electrodes on both sides of the 10 locations using a vapor deposition device (resistance heating vapor deposition device manufactured by Cryovac, product name: CVZ-RHD300-08). to form a lamination region. (2) Cut out each laminated region to obtain 10 laminated bodies.
  • the piezoelectric constant d 31 of each laminate was measured using a piezoelectric constant measurement device (manufactured by Lead Techno, Piezometer System, product name: LPF-03), and the arithmetic mean value be the piezoelectric constant d31 of the organic piezoelectric film.
  • the piezoelectric constant d 31 was measured in detail according to the following (3-1) to (3-7).
  • (3-1) Both ends of the film were clamped with a clip-shaped probe so that the measured length would be (8 to 15 mm).
  • the load applied to the film from the probe was set to 1N and left still. (3-3) The amount of electric charge A generated when a force of 1N was applied to extend the film was measured.
  • Weight average molecular weights were determined by gel permeation chromatography (GPC). Specifically, a 0.5% by mass solution obtained by dissolving a (meth)acrylic polymer in tetrahydrofuran was used as a measurement sample.
  • the measurement conditions are as follows. Equipment: manufactured by Tosoh Corporation, product number: HLC-8320GPC Column: manufactured by Tosoh Corporation, product number: TSKgel G5000H and TSKgel G3000H Eluent: Tetrahydrofuran Flow rate: 1.0 mL/min Temperature: 40°C Detector: RI Molecular weight standard: standard polystyrene
  • Example 1 Production of Coating Liquid and Organic Piezoelectric Film 1 2.3 g of vinylidene fluoride/trifluoroethylene copolymer A1 and 20.5 g of cyclopentanone as a solvent were mixed in a stoppered flask. , a coating liquid containing vinylidene fluoride/trifluoroethylene copolymer A1 having a mass ratio shown in Table 1 was prepared.
  • the coating liquid produced as described above was applied to the substrate 1 using an applicator and allowed to stand for 30 seconds, followed by a normal pressure vacuum dryer (manufactured by Tokyo Rika Kikai Co., Ltd., product name: VOS-310C). ) for 10 minutes at 65° C., and then dried for 1 hour under reduced pressure to 7 Torr to form a coating film. After that, it was dried at 142° C. for 2 hours with a hot air dryer (product name: LC-113, manufactured by Espec Co., Ltd.), and then slowly cooled to room temperature to form a raw material film. The thickness of the film was measured using a coolant proof micrometer (manufactured by Mitutoyo, product name: MDC-25MX) and found to be 40 ⁇ m. After that, the cover film F1 was attached to the raw material film.
  • the raw material film to which the cover film F1 is attached is connected to the power supply unit so that the cover film F1 faces the application electrode and the base material 1 is used as a ground electrode, A polarization treatment was performed by applying a voltage of 12 kV for 120 minutes, and an organic piezoelectric film 1 was produced.
  • Examples 2-10 and Comparative Examples 1-4 The composition of the coating liquid, the presence or absence of the cover film, the presence or absence of the base material, and the polarization conditions were changed to those shown in Table 1, and the organic piezoelectric film was produced in the same manner as in Example 1 except that the applied voltage and the application time were changed. A film was prepared. Table 1 shows the results of similar measurements on the obtained organic piezoelectric film. However, in Comparative Example 4, during the polarization treatment, the organic piezoelectric film separated from the base material 1 was put on the ground electrode attached to the device and the polarization treatment was performed. The percentages in Table 1 represent percentages by mass of the raw material polymer and other polymers in the entire organic piezoelectric film.

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WO2015064327A1 (ja) * 2013-10-29 2015-05-07 ダイキン工業株式会社 フィルム
WO2015129829A1 (ja) * 2014-02-26 2015-09-03 ダイキン工業株式会社 バイモルフ型圧電フィルム
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
WO2019064739A1 (ja) * 2017-09-29 2019-04-04 株式会社クレハ 圧電フィルムおよびフィルムの製造方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015064327A1 (ja) * 2013-10-29 2015-05-07 ダイキン工業株式会社 フィルム
WO2015129829A1 (ja) * 2014-02-26 2015-09-03 ダイキン工業株式会社 バイモルフ型圧電フィルム
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
WO2019064739A1 (ja) * 2017-09-29 2019-04-04 株式会社クレハ 圧電フィルムおよびフィルムの製造方法

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