TW201707970A - Wound layered film body and method for producing the same - Google Patents

Abstract

A wound layered film body obtained by rolling a layered film, the layered film including: a piezoelectric polymer film including a helical chiral polymer that has a weight-average molecular weight of from 50,000 to 1,000,000 and that has optical activity, the piezoelectric polymer film having a degree of crystallinity obtained by the DSC method of from 20% to 80%, and a product of the degree of crystallinity and a normalized molecular orientation MORc is from 40 to 700 in a case in which a standard thickness of the piezoelectric polymer film, which is measured with a microwave transmission molecular orientation meter, is made to be 50 [mu]m; and a functional layer (X) provided on at least one of the principal planes of the piezoelectric polymer film, wherein the piezoelectric polymer film obtained by removing the functional layer (X) from the layered film has a rate of dimensional change after heating for 30 minutes at 100 DEG C of 1.0% or less in the MD direction.

Description

Film roll layer and manufacturing method thereof

The present invention relates to a film reel body having a polymer piezoelectric film and a method of manufacturing the same.

In recent years, a polymer piezoelectric material using an optically active aliphatic polyester (for example, a polylactic acid-based polymer) has been reported. For example, a polymer piezoelectric material exhibiting a piezoelectric modulus of about 10 pC/N at room temperature by stretching a molded product of polylactic acid is disclosed (for example, see Patent Document 1). In addition, high-voltage electrical properties of about 18 pC/N are achieved by a special alignment method called a forging method in order to make the polylactic acid crystals have a high alignment (see, for example, Patent Document 2). Patent Document 1: Japanese Patent Laid-Open No. Hei 5-152638. Patent Document 2: Japanese Patent Laid-Open Publication No. 2005-213376

[Problems to be Solved by the Invention] However, in order to protect the polymer piezoelectric body or the polymer piezoelectric body and other members (polymer film, glass, electrode, etc.), the polymer may be used. At least a portion of the piezoelectric body is placed in contact with the piezoelectric polymer. As this layer, an adhesive layer is sometimes used. Further, when a polymer piezoelectric body is used to actually manufacture a sensor or an actuator as an element, industrially, from the viewpoint of productivity, it is preferable to employ a continuous roll to roll. Process. Therefore, it is necessary to supply a rewinding body (roller body) obtained by winding a polymer piezoelectric body in a long strip. At this time, if the roll body of the polymer piezoelectric body is provided with the adhesive layer, it is not necessary to form an adhesive layer in the subsequent step, and the simplification of the steps can be achieved. Further, since a continuous process using a roll-to-roller can be employed in a state in which an adhesive layer is formed, the total productivity up to the production of the component is improved. Here, in the continuous process of the roll-to-roll, it is necessary to prevent bending of the polymer piezoelectric body between the rolls, and to advance in the step (Machine Direction (MD) direction) in the polymer piezoelectric body. Produces tension. Further, the polymer piezoelectric body containing an aliphatic polyester (helical chiral polymer) such as polylactic acid has low heat resistance, and may be heated in the step of forming the adhesive layer on the polymer piezoelectric body. Stretching occurs in the polymer piezoelectric body due to the tension, the dimensional change rate of the polymer piezoelectric body is deteriorated, or the aliphatic polyester such as polylactic acid is decomposed by heat, and the heat resistance of the polymer piezoelectric body is deteriorated. deterioration. Further, in order to cause the piezoelectric polymer to exhibit piezoelectricity, it is preferred that the molecular chains are aligned in one direction, but there is a problem in that it is easily torn in the alignment direction. Therefore, when a polymer piezoelectric body in which the dimensional change rate is deteriorated and the molecular chain is aligned mainly in one direction is used as the element, there is a difference in shrinkage between the polymer piezoelectric body and another member in which the layer is laminated. Cracks in the piezoelectric body.

As a result of intensive research, the present inventors have found that a film-rolled layer obtained by winding a laminated film having a polymer layer containing a polyester (helical chiral polymer) and a functional layer such as an adhesive layer into a roll shape By reducing the dimensional change rate of the polymer piezoelectric body containing the helical chiral polymer, the occurrence of cracks in the piezoelectric polymer film during heating is suppressed, and the heat resistance of the polymer piezoelectric film is suppressed. Sexual improvement.

The present invention has been made in view of the above, and it is an object of the invention to provide a film roll layer which is excellent in moisture heat resistance of a polymer piezoelectric film and which suppresses generation of cracks in a piezoelectric polymer film during heating. Body and its manufacturing method. [Means for solving the problem]

Specific means for achieving the above problems are as follows, for example. <1> A film roll layer obtained by winding a laminated film into a roll shape, the laminated film comprising: a polymer piezoelectric film comprising an optically active spiral having a weight average molecular weight of 50,000 to 1,000,000 The chiral polymer (A) has a crystallinity of 20% to 80% obtained by a differential scanning calorimetry (DSC) method, and a reference thickness measured by a microwave transmission type molecular alignment meter is set. The product of the normalized molecular alignment MORc at 50 μm and the crystallinity is 40 to 700; and the functional layer (X) is disposed on at least one main surface of the piezoelectric polymer film; and is self-contained at 100 ° C The dimensional change rate of the piezoelectric polymer film obtained by removing the functional layer (X) in the laminated film after heating for 30 minutes is 1.0% or less in the MD direction. <2> The film-rolled layer body according to <1>, wherein the functional layer (X) has an acid value of 10 mgKOH/g or less. <3> The film reel body according to <1> or <2>, wherein the functional layer (X) is an adhesive layer. The film roll layer body according to any one of <1> to <3> wherein the functional layer (X) has an acid value of 0.01 mgKOH/g or more. The film roll layer body according to any one of <1> to <4> wherein the total nitrogen amount in the functional layer (X) is 0.05% by mass to 10% by mass. The film roll layer body according to any one of <1> to <5> wherein the functional layer (X) is in contact with the polymer piezoelectric film. The film roll layer body according to any one of <1> to <6> wherein the laminated film has a refractive index adjustment between the polymer piezoelectric film and the functional layer (X) At least one layer of a layer, an easy adhesion layer, a hard coat layer, an antistatic layer, and an anti-blocking layer. The film-rolled layer body according to any one of <1> to <7> wherein the polymer piezoelectric film contains 100 parts by mass of the helical chiral polymer (A). The stabilizer (B) having a weight average molecular weight of from 200 to 60,000 to 0.01 parts by mass to 10 parts by mass per one or more functional groups in the group consisting of a free carboethylene imino group, an epoxy group, and an isocyanate group. <9> The film reel body according to <8>, wherein the stabilizer (B) comprises one or more selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group. a stabilizer (B1) having a functional group and a weight average molecular weight of 200 to 900, and having two or more groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group in one molecule A stabilizer (B2) having one or more functional groups and having a weight average molecular weight of 1,000 to 60,000. The film roll layer body according to any one of <1> to <9> wherein the polymer piezoelectric film has an internal haze of 50% or less with respect to visible light, and is at 25 ° C. The piezoelectric constant d ₁₄ measured by the stress-charge method is 1 pC/N or more. The film roll layer body according to any one of <1> to <10> wherein the polymer piezoelectric film has an internal haze of 13% or less with respect to visible light, and is relative to the 100 parts by mass of the helical chiral polymer (A), comprising one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group, and having a weight average molecular weight of 200 to 60,000 The stabilizer (B) is 0.01 parts by mass to 2.8 parts by mass. The film-rolled layer body according to any one of <1>, wherein the helical chiral polymer (A) has a repeating unit represented by the following formula (1) A polylactic acid-based polymer of the main chain.

[Chemical 1]

The film-rolled layer body according to any one of <1> to <12> wherein the optical purity of the helical chiral polymer (A) is 95.00% or more. The film roll layer body according to any one of the above aspects, wherein the content of the helical chiral polymer (A) in the polymer piezoelectric film is 80% by mass or more . The film roll layer body according to any one of <1> to <14> wherein the laminated film further includes a configuration in which the polymer pressure is observed from the functional layer (X) A release film on the opposite side of the side of the electric film. <16> The film-rolled layer body according to <15>, wherein the laminated film has a length in the MD direction of 10 m or more.

<17> A method of producing a film roll layer, which is a method of producing a film roll layer body according to <15> or <16>, comprising: a functional layer to form the functional layer (X) a step of forming a forming agent on the main surface of the release film to form the functional layer (X); on a side opposite to the side on which the release film is disposed, as viewed from the functional layer (X), a step of bonding the functional layer (X) to the polymer piezoelectric film to form the laminated film, and a step of winding the formed laminated film into a roll shape. <18> A method of producing a film roll layer, which is a method of producing a film roll layer body according to <15> or <16>, comprising: a functional layer to form the functional layer (X) a step of applying a forming agent to at least one main surface of the piezoelectric polymer film and drying the applied functional layer forming agent at a temperature of 90 ° C or lower to form a functional layer (X); a step of forming the laminated film by bonding the functional layer (X) and the release film to the side opposite to the side on which the piezoelectric film is disposed, as viewed from the functional layer (X) And a step of winding the formed laminated film into a roll shape. <19> The method for producing a film-rolled layer body according to <18>, wherein the functional layer (X) is an adhesive layer, and the functional layer forming agent is an adhesive. [Effects of the Invention]

According to the present invention, it is possible to provide a film roll layer body in which generation of cracks in the piezoelectric polymer film during heating is suppressed, and which is excellent in moisture heat resistance of the polymer piezoelectric film, and a method for producing the same.

Hereinafter, an embodiment of the film wound layer body of the present invention will be described. In the present specification, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit and the upper limit. In addition, in the present specification, the "film" includes not only a person generally referred to as a "film" but also a concept commonly referred to as a "sheet". In the present specification, the "(meth)acrylic group" means at least one of an acryl group and a methacryl group.

In addition, in this specification, a film surface means the main surface of a film. Here, the "main surface" means a surface having the largest area among the surfaces of the polymer piezoelectric film. The piezoelectric polymer film used in the present invention may have two or more main faces. For example, when the polymer piezoelectric film has a face A of 10 mm × 0.3 mm square on each side, a face B of 3 mm × 0.3 mm square, and a face C of 10 mm × 3 mm square, the piezoelectric polymer The main face of the film is face C and has two major faces. In the present specification, the "MD direction" means the direction of the film (Machine Direction), and the "TD direction" means the direction orthogonal to the MD direction and parallel to the main surface of the film. (Transverse Direction).

<Film roll layer> The film roll layer body according to the embodiment of the present invention is obtained by winding a laminated film into a roll shape, and the build-up film includes a polymer piezoelectric film containing a weight average molecular weight of 50,000 to 100. The optically active helical chiral polymer (A) has a crystallinity of 20% to 80% by the DSC method and a reference thickness of 50 μm as measured by a microwave transmission type molecular alignment meter. a product of the normalized molecular alignment MORc and the crystallinity of 40 to 700; and a functional layer (X) disposed on at least one main surface of the piezoelectric polymer film; and at 100 ° C The dimensional change rate of the polymer piezoelectric film obtained by removing the functional layer (X) in the laminated film after heating for 30 minutes is 1.0% or less in the MD direction.

The film roll layer of the present embodiment is obtained by winding a laminated film having a polymer piezoelectric film and a functional layer (X) provided on at least one main surface of the polymer piezoelectric film in a roll shape, and is 100 The dimensional change rate when the polymer piezoelectric film obtained by removing the functional layer (X) from the laminated film was heated for 30 minutes at a temperature of ° C was 1.0% or less in the MD direction. Therefore, for example, when a laminated body is formed using a film roll layer, generation of cracks in the piezoelectric polymer film during heating is suppressed, and a helical chiral polymer contained in the polymer piezoelectric film (A) The decomposition of the polymer film is suppressed, and the polymer piezoelectric film is excellent in moist heat resistance. Further, when the polymer piezoelectric film is heated at 100 ° C for 30 minutes, the dimensional change ratio is 1.0% or less in the MD direction, so that the dimensional stability is excellent, and it is incorporated in a device such as a speaker or a touch panel. When used, the size is hard to change, and the occurrence of malfunction of components and the like is suppressed.

Further, the film wound layer body of the present embodiment has a polymer piezoelectric film comprising an optically active helical chiral polymer (A) having a weight average molecular weight (Mw) of 50,000 to 1,000,000 ( Hereinafter, it is also referred to as "spiral chiral polymer (A)"). When the weight average molecular weight of the helical chiral polymer (A) is 50,000 or more, the mechanical strength when the helical chiral polymer (A) is formed into a molded body is improved. When the weight average molecular weight of the helical chiral polymer (A) is 1,000,000 or less, the moldability of the polymer piezoelectric film is improved by molding (for example, extrusion molding).

The crystallinity of the piezoelectric polymer film obtained by the DSC method is 20% to 80%. Therefore, the piezoelectric piezoelectric film has a good balance between piezoelectricity, transparency, and longitudinal crack strength (tear strength in a specific direction), and when the piezoelectric polymer film is stretched, it is difficult to cause whitening or cracking. Easy to manufacture. More specifically, the piezoelectricity of the piezoelectric polymer film is maintained high by the crystallinity of 20% or more, and the longitudinal crack strength of the piezoelectric polymer film can be suppressed by the crystallinity of 80% or less. And transparency has declined.

In the piezoelectric polymer film, the product of the normalized molecular alignment MORc and the crystallinity when the reference thickness measured by the microwave transmission type molecular alignment meter is 50 μm is 40 to 700. By adjusting to this range, the piezoelectric piezoelectric film has a good balance between piezoelectricity and transparency, and also has high dimensional stability, and the decrease in longitudinal crack strength is suppressed.

[Polymer piezoelectric film] The film wound layer body of the present embodiment contains an optically active helical chiral polymer (A), and the crystallinity obtained by the DSC method is 20% to 80%, and will be microwaved. The product of the normalized molecular alignment MORc and the crystallinity when the reference thickness measured by the transmission type molecular alignment meter is 50 μm is 40 to 700. Hereinafter, the physical properties of the piezoelectric polymer film, the components contained in the piezoelectric polymer film, and the like will be described in detail.

[The optically active helical chiral polymer (A)] The piezoelectric polymer film used in the present embodiment contains an optically active helical chiral polymer (A). The optically active helical chiral polymer (A) refers to a polymer having a molecular structure of a helical structure and having a molecular optical activity and a weight average molecular weight of 50,000 to 1,000,000. Examples of the helical chiral polymer (A) include a polypeptide, cellulose, a cellulose derivative, a polylactic acid-based polymer, polypropylene oxide, and poly(β-hydroxybutyric acid). Examples of the polypeptide include poly(glutaric acid γ-benzyl), poly(glutaric acid γ-methyl), and the like. Examples of the cellulose derivative include cellulose acetate and cyanoethyl cellulose.

The optical purity of the helical chiral polymer (A) is preferably 95.00% ee or more, more preferably 97.00% ee or more, and still more preferably 99.00% ee from the viewpoint of improving the piezoelectricity of the piezoelectric polymer film. Above, it is particularly good at 99.99% ee or more. Ideally 100.00% ee. When the optical purity of the helical chiral polymer (A) is within the above range, the deposition property of the piezoelectric polymer crystal is increased, and as a result, the piezoelectricity is high.

In the present embodiment, the optical purity of the helical chiral polymer (A) is a value calculated by the following formula. Optical purity (%ee)=100×|L volume-D volume|/(L body mass + D volume) That is, "the amount of the L-body of the helical chiral polymer (A) [% by mass] The amount (absolute value) of the amount (% by mass) of the D body of the helical chiral polymer (A) is divided by (divisible) "the amount of the L body of the helical chiral polymer (A) [% by mass] The value obtained by multiplying (multiplied) "100" by the value obtained by the sum of the amounts (% by mass) of the D body of the helical chiral polymer (A) is set to optical purity.

In addition, the amount [% by mass] of the L body of the helical chiral polymer (A) and the amount of the D body of the helical chiral polymer (A) [% by mass] are used by using high-speed liquid chromatography (High). The value obtained by the method of Performance Liquid Chromatography, HPLC). The details of the specific measurement will be described later.

Among the above-mentioned helical chiral polymers (A), a polymer having a main chain including a repeating unit represented by the following formula (1) is preferred from the viewpoint of improving optical purity and improving piezoelectricity. .

[Chemical 2]

A polylactic acid-based polymer is exemplified as the compound having a repeating unit represented by the above formula (1) as a main chain. Among them, polylactic acid is preferred, and a homopolymer of L-lactic acid (Poly-L-Lactic-Acid (PLLA)) or a homopolymer of D-lactic acid (poly-L-lactic acid (Poly-) is preferred. D-Lactic-Acid, PDLA)).

The polylactic acid-based polymer means "polylactic acid", "L-lactic acid or a copolymer of D-lactic acid and a polyfunctional compound copolymerizable", or a mixture of the two. It is known that the "polylactic acid" is a polymer obtained by polymerizing and polymerizing lactic acid by an ester bond, and can be obtained by a lactide method via lactide in a solvent and in a solvent. The lactic acid is heated under reduced pressure, and is produced by a direct polymerization method in which polymerization is carried out while removing water. Examples of the "polylactic acid" include a homopolymer of L-lactic acid, a homopolymer of D-lactic acid, a block copolymer of a polymer containing at least one of L-lactic acid and D-lactic acid, and L-containing copolymer. a graft copolymer of a polymer of at least one of lactic acid and D-lactic acid.

Examples of the "polyfunctional compound copolymerizable" include glycolic acid, dimethyl glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxypropionic acid, and 3-hydroxypropionic acid. 2-hydroxyvaleric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 2-hydroxyhexanoic acid, 3-hydroxyhexanoic acid, 4-hydroxyhexanoic acid, 5-hydroxyhexanoic acid, 6- Hydroxycarboxylic acid, 6-hydroxymethylhexanoic acid, hydroxycarboxylic acid such as mandelic acid, glycolide, β-methyl-δ-valerolactone, γ-valerolactone, ε-caprolactone, etc. Cyclic esters, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, sebacic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, terephthalic acid Polycarboxylic acids, such anhydrides, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butane Alcohol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, neopentyl Polyol such as alcohol, tetramethylene glycol or 1,4-hexanedimethanol; polysaccharides such as cellulose; aminocarboxylic acids such as α-amino acid.

The "polyfunctional compound which can be copolymerized" is, for example, a compound described in paragraph 0028 of the International Publication No. 2013/054918.

Examples of the "copolymer of L-lactic acid or D-lactic acid and a polyfunctional compound copolymerizable" include a block copolymer or a graft copolymer having a polylactic acid sequence capable of generating a spiral crystal.

Further, the concentration of the structure derived from the copolymer component in the helical chiral polymer (A) is preferably 20 mol% or less. For example, when the helical chiral polymer (A) is a polylactic acid-based polymer, the structure derived from lactic acid in the polylactic acid-based polymer and the structure derived from a compound (copolymer component) copolymerizable with lactic acid are used. The copolymer component is preferably 20 mol% or less in total of the molar number.

The helical chiral polymer (A) (for example, a polylactic acid-based polymer) can be produced by, for example, the following method: Japanese Patent Laid-Open No. 59-096123, and Japanese Patent Laid-Open No. Hei 7-033861 A method of obtaining a helical chiral polymer (A) by directly dehydrating and condensing lactic acid, or using lactide as a cyclic dimer of lactic acid as described in U.S. Patent No. 2,668,182 and U.S. Patent No. 4,057,357. The method of ring polymerization. Furthermore, in order to set the optical purity of the helical chiral polymer (A) (for example, a polylactic acid-based polymer) obtained by each of the above-described production methods to 95.00% or more, for example, when the polylactic acid is produced by the lactide method, In the case, it is preferred to carry out polymerization by increasing the optical purity to a lactone having an optical purity of 95.00% ee or more by a crystallization operation.

The weight average molecular weight of the helical chiral polymer (A) ≫ The weight average molecular weight (Mw) of the helical chiral polymer (A) used in the present embodiment is 50,000 to 1,000,000. When the weight average molecular weight of the helical chiral polymer (A) is 50,000 or more, the mechanical strength when the helical chiral polymer (A) is formed into a molded body is improved. The weight average molecular weight of the helical chiral polymer (A) is preferably 100,000 or more, and more preferably 150,000 or more, from the viewpoint of further improving the mechanical strength at the time of forming the molded body. On the other hand, when the weight average molecular weight of the helical chiral polymer (A) is 1,000,000 or less, the moldability of the polymer piezoelectric film is improved by molding (for example, extrusion molding). The weight average molecular weight of the helical chiral polymer (A) is preferably 800,000 or less, and more preferably 300,000 or less, from the viewpoint of further improving the moldability at the time of obtaining the polymer piezoelectric film.

In addition, the molecular weight distribution (Mw/Mn) of the helical chiral polymer (A) is preferably from 1.1 to 5, more preferably from 1.2 to 4, from the viewpoint of the strength of the polymer piezoelectric film. More preferably, it is 1.4 to 3. Further, the weight average molecular weight Mw and the molecular weight distribution (Mw/Mn) of the helical chiral polymer (A) (for example, a polylactic acid-based polymer) are obtained by using a gel permeation chromatograph (GPC). The measurement was carried out by the following GPC measurement method.

-GPC measuring device - GPC-100 - Pipe column manufactured by Waters - Shodex LF-804 - Preparation of sample - Spiral hand at 40 ° C The polymer (A) is dissolved in a solvent (for example, chloroform) to prepare a sample solution having a concentration of 1 mg/mL. - Measurement conditions - 0.1 mL of the sample solution was introduced into the column at a flow rate of a solvent [chloroform], a temperature of 40 ° C, and a flow rate of 1 mL/min.

A sample refractometer is used to determine the concentration of the sample in the sample solution separated by the column. A general calibration curve was prepared using a polystyrene standard sample, and the weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) of the helical chiral polymer (A) were calculated.

A commercially available polylactic acid can also be used as the polylactic acid-based polymer as an example of the helical chiral polymer (A). Examples of the commercially available polylactic acid include PURASORB (PD, PL) manufactured by PURAC Co., Ltd., and LACEA (H-100, H-400) manufactured by Mitsui Chemicals, Inc. naphthalene Qiwo Ke LLC (NatureWorks LLC) manufactured by British Gill ^TM biopolymers (Ingeo ^TM biopolymer) and the like.

When a polylactic acid-based polymer is used as the helical chiral polymer (A), the weight average molecular weight (Mw) of the polylactic acid-based polymer is preferably 50,000 or more, preferably by a lactide method or directly A spiral chiral polymer (A) is produced by a polymerization method.

The piezoelectric polymer film used in the present embodiment may contain only one type of helical chiral polymer (A), and may be contained in two or more types. In the piezoelectric polymer film used in the present embodiment, the content of the helical chiral polymer (A) (the total content in the case of two or more kinds, the same applies hereinafter) is not particularly limited, but is relative to the piezoelectric polymer. The total mass of the film is preferably 80% by mass or more. When the content is 80% by mass or more, the piezoelectric constant tends to be further increased.

≪MD size change rate MDIn the film roll layer of the present embodiment, the MD direction dimension when the polymer piezoelectric film obtained by removing the functional layer (X) from the build-up film is heated at 100 ° C for 30 minutes The rate of change (MD size change rate) is 1.0% or less. The smaller the dimensional change rate, the higher the dimensional stability. The dimensional change rate in the MD direction is obtained as follows. First, the functional layer (X) is removed from the laminated film, cut 50 mm in the extending direction (MD direction), and cut 50 mm in the direction orthogonal to the extending direction (TD direction), and cut out 50 mm × 50 A rectangular film of mm. Further, when the laminated film has a release film, another layer, or the like, the release film, other layers, and the like are also removed together with the functional layer (X). The rectangular film was suspended in an oven set at 100 ° C and annealed for 30 minutes. Thereafter, the size of the rectangular side length of the film in the MD direction before and after the annealing treatment was measured by a high-precision digital length measuring machine (manufactured by Mitutoyo Co., Ltd., Litematic VL-50AS). Further, the dimensional change ratio (%) was calculated according to the following formula, and the dimensional stability was evaluated. (Formula) dimensional change rate (%) = 100 × | (edge length in the MD direction before annealing) - (edge length in the MD direction after annealing) | / (edge length in the MD direction before annealing)

From the viewpoint of further improving the dimensional stability, the dimensional change ratio in the MD direction is preferably 0.9% or less, more preferably 0.8% or less.

≪ Crystallinity ≫ The crystallinity of the polymer piezoelectric film is determined by the DSC method. The polymer piezoelectric film has a crystallinity of 20% to 80%, preferably 30% to 70%, more preferably 35% to 60%. When the degree of crystallinity is within the above range, the piezoelectric piezoelectric film has a good balance of piezoelectricity, transparency, and longitudinal crack strength, and when the piezoelectric polymer film is stretched, it is difficult to cause whitening or cracking. Manufacturing. The piezoelectricity of the piezoelectric polymer film is maintained high by a crystallinity of 20% or more. Further, by having a crystallinity of 80% or less, the longitudinal crack strength and the transparency can be suppressed from being lowered.

For example, the crystallinity of the piezoelectric polymer film can be adjusted to a range of 20% to 80% by adjusting the conditions of crystallization and elongation when the piezoelectric polymer film is produced.

The normalized molecular alignment MORc of the ≪standardized molecular alignment MORc≫ polymer piezoelectric film is preferably 2.0 to 15.0. The normalized molecular alignment MORc is a value determined based on the "molecular alignment degree MOR" which is an index indicating the degree of alignment of the helical chiral polymer (A). When the normalized molecular alignment MORc is 2.0 or more, the molecular chain of the helical chiral polymer (A) arranged in the extending direction (for example, a polylactic acid molecular chain) is large, and as a result, the formation ratio of the alignment crystal becomes high, and the polymer pressure is high. The electric film can exhibit higher piezoelectricity. When the normalized molecular alignment MORc is 15.0 or less, the longitudinal crack strength of the piezoelectric polymer film is further improved.

Here, the molecular orientation degree MOR (Molecular Orientation Ratio) is measured by the following microwave measurement method. In other words, in the microwave resonance waveguide of a well-known microwave transmission type molecular alignment meter (also referred to as a microwave molecular alignment degree measuring apparatus), the surface (film surface) of the polymer piezoelectric film is arranged perpendicular to the traveling direction of the microwave. Polymer piezoelectric film. In the state in which the sample is continuously irradiated with the microwave in which the vibration direction is shifted in one direction, the polymer piezoelectric film is rotated by 0 to 360 in a plane perpendicular to the traveling direction of the microwave, and the microwave of the sample is measured. The strength is used to determine the molecular orientation MOR.

The normalized molecular alignment MORc is a molecular orientation MOR when the reference thickness tc is 50 μm, and can be obtained by the following formula. MORc=(tc/t)×(MOR-1)+1 (tc: reference thickness to be corrected, t: thickness of polymer piezoelectric film) Standardized molecular alignment MORc can be measured by a known molecular alignment meter, such as prince measurement The microwave molecular molecular alignment meter MOA-2012A or MOA-6000 manufactured by Oji Keisoku Kiki Co., Ltd. is measured at a resonance frequency around 4 GHz or 12 GHz.

The normalized molecular alignment MORc of the polymer piezoelectric film is preferably from 3.0 to 15.0, more preferably from 3.5 to 10.0, particularly preferably from 4.0 to 8.0. Further, from the viewpoint of further improving the adhesion between the polymer piezoelectric film and the intermediate layer, the normalized molecular alignment MORc is preferably 7.0 or less.

For example, when the polymer piezoelectric film is a stretched film, the normalized molecular alignment MORc can be controlled by heat treatment conditions (heating temperature and heating time) before stretching, elongation conditions (stretching ratio, elongation temperature, and elongation speed).

Furthermore, the normalized molecular alignment MORc can also be converted into a birefringence Δn obtained by dividing the phase difference (delay) by the thickness of the film. Specifically, the retardation can be measured using the RETS100 manufactured by Otsuka Electronics Co., Ltd. In addition, MORc is approximately in a linear proportional relationship with Δn, and when Δn is 0, MORc becomes 1. For example, when the helical chiral polymer (A) is a polylactic acid-based polymer and the birefringence Δn of the polymer piezoelectric film is measured at a measurement wavelength of 550 nm, if the normalized molecular alignment MORc is 2.0, it can be converted into a double The refractive index Δn 0.005, if the normalized molecular alignment MORc is 4.0, can be converted into a birefringence Δn0.01.

≪ Standardized molecular alignment MORc and crystallinity accumulation In the present embodiment, the product of the crystallinity of the polymer piezoelectric film and the normalized molecular alignment MORc is 40 to 700. By adjusting to this range, the piezoelectric piezoelectric film has a good balance between piezoelectricity and transparency, and also has high dimensional stability, and the decrease in longitudinal crack strength is suppressed. The product of the normalized molecular alignment MORc and the crystallinity of the piezoelectric polymer film is preferably from 40 to 600, more preferably from 100 to 500, particularly preferably from 125 to 400, and particularly preferably from 150 to 300.

For example, the product can be adjusted to the above range by adjusting the conditions of crystallization and elongation when the piezoelectric polymer film is produced.

Further, the normalized molecular alignment MORc can be controlled by conditions for crystallization (for example, heating temperature and heating time) and elongation conditions (for example, stretching ratio, elongation temperature, and elongation speed) when the polymer piezoelectric film is produced.

≪Piezoelectric constant d ₁₄ (stress-charge method) 压电 The piezoelectricity of the piezoelectric polymer film can be evaluated, for example, by measuring the piezoelectric constant d ₁₄ of the piezoelectric polymer film. Hereinafter, an example of a method of measuring the piezoelectric constant d ₁₄ by the stress-charge method will be described.

First, the piezoelectric polymer film was cut into 150 mm in a direction of 45° with respect to the extending direction (MD direction), and cut into 50 mm in a direction orthogonal to the direction of 45° to form a rectangular shape. Test piece. Then, the obtained test piece was placed on a test stand of SIP-600 manufactured by Showa Vacuum Co., Ltd., and the vapor deposition thickness of aluminum (hereinafter referred to as Al) was changed to about 50 nm, and the test piece was used. Al is evaporated on one side. Then, vapor deposition was performed on the other surface of the test piece in the same manner, and Al was coated on both surfaces of the test piece to form a conductive layer of Al.

A test piece of 150 mm × 50 mm in which a conductive layer of Al was formed on both sides was cut into 120 mm in a direction of 45° with respect to the extending direction (MD direction) of the polymer piezoelectric film, and was 45 The direction of the direction of ° was cut into 10 mm, and a rectangular film of 120 mm × 10 mm was cut out. This was used as a sample for measuring piezoelectric constants.

The obtained sample was placed in a tensile tester (manufactured by Ahn Thom, TENSILON RTG-1250) having a distance between the chucks of 70 mm in a manner that does not relax. The force is periodically applied in a manner that the crosshead speed is 5 mm/min and the applied force is reciprocated between 4 N and 9 N. At this time, in order to measure the amount of charge generated in the sample corresponding to the applied force, a capacitor having a capacitance of Qm (F) is connected in parallel with the sample, and the voltage between the terminals of the capacitor Cm (95 nF) is measured via a buffer amplifier. V. The above measurement was carried out at a temperature of 25 °C. The generated charge amount Q(C) is calculated as a product of the capacitor capacitance Cm and the inter-terminal voltage Vm. The piezoelectric constant d ₁₄ is calculated by the following formula. d ₁₄ =(2×t)/L×Cm·ΔVm/ΔF t: sample thickness (m) L: distance between chucks (m) Cm: capacitor capacitance connected in parallel (F) ΔVm/ΔF: change with respect to force Ratio of voltage change between capacitor terminals

The higher the piezoelectric constant d _{14 is, the} more the displacement of the piezoelectric piezoelectric film applied to the piezoelectric polymer film is reversed, and the voltage generated is relatively higher with respect to the force applied to the piezoelectric polymer film. Large, useful as a polymer piezoelectric film. Specifically, in the piezoelectric polymer film of the present embodiment, the piezoelectric constant d ₁₄ measured by the stress-charge method at 25 ° C is preferably 1 pC/N or more, more preferably 3 pC/. N or more, more preferably 5 pC/N or more, particularly preferably 6 pC/N or more. In addition, the upper limit of the piezoelectric constant d ₁₄ is not particularly limited, but in terms of the balance of transparency and the like, the polymer piezoelectric film using the helical chiral polymer is preferably 50 pC/N or less. More preferably, it is 30 pC/N or less. Further, similarly, from the viewpoint of the balance of transparency, the piezoelectric constant d ₁₄ measured by the resonance method is preferably 15 pC/N or less.

≪Transparency (internal haze) 透明 The transparency of the piezoelectric polymer film used in the present embodiment can be evaluated, for example, by visual observation or haze measurement. The internal haze of the polymer piezoelectric film with respect to visible light (hereinafter also referred to as "internal haze") is preferably 50% or less, more preferably 20% or less, further preferably 13% or less, and further preferably It is 5% or less, particularly preferably 2.0% or less, and most preferably 1.0% or less. The piezoelectric vibrating membrane used in the present embodiment has a lower internal haze, and is preferably 0.01% to 15%, more preferably 0.01%, from the viewpoint of balance between piezoelectric constant and the like. 10%, more preferably 0.1% to 5%, particularly preferably 0.1% to 1.0%.

In the present embodiment, the "internal haze" means a haze other than the haze formed by the shape of the outer surface of the polymer piezoelectric film. In addition, the "internal haze" described here is a value measured on a polymer piezoelectric film at 25 ° C in accordance with JIS-K7105.

More specifically, the internal haze (hereinafter also referred to as "internal haze H1") means a value measured as follows. In other words, first, the haze in the optical path length direction (hereinafter also referred to as "haze H2") is measured for a unit having an optical path length of 10 mm filled with eucalyptus oil. Then, the polymer piezoelectric film was immersed in the eucalyptus oil of the unit so that the optical path length direction of the unit became parallel to the normal direction of the film, and the optical path length direction of the unit immersed in the polymer piezoelectric film was measured. Haze (hereinafter, also referred to as "haze H3"). Both haze H2 and haze H3 were measured at 25 ° C according to JIS-K7105. Based on the measured haze H2 and haze H3, the internal haze H1 was obtained from the following equation. Internal haze (H1) = haze (H3) - haze (H2)

The measurement of the haze H2 and the haze H3 can be performed, for example, using a haze measuring machine [manufactured by Tokyo Denshoku Co., Ltd., TC-HIII DPK]. In addition, as the eucalyptus oil, for example, Shin-Etsu Silicone (trademark) manufactured by Shin-Etsu Chemical Co., Ltd., model number KF-96-100CS can be used.

Further, the thickness of the piezoelectric polymer film is not particularly limited, but is preferably 10 μm to 400 μm, more preferably 20 μm to 200 μm, still more preferably 20 μm to 100 μm, and particularly preferably 20 μm to 80 μm. Mm.

[Stabilizer (B)] The piezoelectric polymer film used in the present embodiment may further contain one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group. A compound having a weight average molecular weight of from 200 to 60,000 is used as the stabilizer (B). Thereby, the heat resistance of the polymer piezoelectric film is further improved. Further, in the polymer piezoelectric film, it is preferable that the stabilizer (B) has one or more selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group in one molecule. Functional group. As the stabilizer (B), "stabilizer (B)" described in paragraph 0039 to paragraph 0055 of International Publication No. 2013/054918 can be used.

As a compound (carbodiimide compound) containing a carbodiimide group in one molecule which can be used as a stabilizer (B), a monocarbodiimide compound or a polycarbodiimide compound can be cited. a cyclic carbodiimide compound. As the monocarbodiimide compound, dicyclohexylcarbodiimide, bis-2,6-diisopropylphenylcarbodiimide or the like is suitable. Further, as the polycarbodiimide compound, those produced by various methods can be used. A method for producing a polycarbodiimide by a prior art can be used (for example, U.S. Patent No. 2,941,956, Japanese Patent Publication No. Sho 47-33279, "J. Org. Chem." 28, 2069 Manufactured by -2075 (1963), "Chemical Review" 1981, Vol. 81 No. 4, p619-621). Specifically, a carbodiimide compound described in Japanese Patent No. 4,084,953 can also be used. Examples of the polycarbodiimide compound include poly(4,4'-dicyclohexylmethane carbodiimide) and poly(N,N'-di-2,6-diisopropylphenylcarbon). Dimethyleneimine), poly(1,3,5-triisopropylphenylene-2,4-carbodiimide), and the like. The cyclic carbodiimide compound can be synthesized by the method described in JP-A-2011-256337, JP-A-2013-256485, and the like. Commercially available products can be used as the carbodiimide compound, and, for example, B2756 (trade name) manufactured by Tokyo Chemical Industry Co., Ltd., and Carbodilite LA-1 manufactured by Nisshinbo Chemical Co., Ltd. , Stabaxol P, Stabaxol P400, and Stabaxol I (all trade names) manufactured by Rhein Chemie.

As the compound (isocyanate compound) containing an isocyanate group in one molecule which can be used as the stabilizer (B), 3-(triethoxydecyl)propyl isocyanate and 2,4-toluene diisocyanate are mentioned. , 2,6-toluene diisocyanate, isophthalic diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenyl Methane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and the like.

Examples of the epoxy group-containing compound (epoxy compound) which can be used as the stabilizer (B) in one molecule include phenyl glycidyl ether, diethylene glycol diglycidyl ether, and bisphenol A-bi-condensation. Glycerol ether, hydrogenated bisphenol A-diglycidyl ether, phenol novolac type epoxy resin, cresol novolac type epoxy resin, epoxidized polybutadiene, and the like.

The weight average molecular weight of the stabilizer (B) is from 200 to 60,000, more preferably from 200 to 30,000, still more preferably from 300 to 18,000, as described above. When the weight average molecular weight of the stabilizer (B) is within the above range, the stabilizer is more likely to move, and the effect of improving the moist heat resistance is more effectively obtained. The weight average molecular weight of the stabilizer (B) is particularly preferably from 200 to 900. Further, the weight average molecular weight is from 200 to 900, and the number average molecular weight is approximately from 200 to 900. Further, when the weight average molecular weight is from 200 to 900, the molecular weight distribution may be 1.0. In this case, the "weight average molecular weight of 200 to 900" may be simply referred to as "molecular weight of 200 to 900".

When the polymer piezoelectric film contains the stabilizer (B), the polymer piezoelectric film may contain only one stabilizer (B), or may contain two or more kinds. When the polymer piezoelectric film contains the helical chiral polymer (A) and the stabilizer (B), the content of the stabilizer (B) is 100 parts by mass relative to the helical chiral polymer (A) (two or more cases) The following is the total content. The same as the following) is preferably 0.01 parts by mass to 10 parts by mass, more preferably 0.01 parts by mass to 5 parts by mass, still more preferably 0.01 parts by mass to 3 parts by mass, still more preferably 0.01 parts by mass to 2.8 parts by mass. The mass part is more preferably from 0.1 part by mass to 2.8 parts by mass, particularly preferably from 0.5 part by mass to 2 parts by mass. When the content is 0.01 parts by mass or more, the moist heat resistance is further improved. In addition, when the content is 10 parts by mass or less, the decrease in transparency is further suppressed.

Preferred examples of the stabilizer (B) include one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group, and the number average molecular weight thereof. a stabilizer (B1) of 200 to 900 and one or more functional groups having two or more selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group in one molecule, and the weight The stabilizer (B2) having an average molecular weight of 1,000 to 60,000 is used in this form. Further, the stabilizer (B1) having a number average molecular weight of 200 to 900 has a weight average molecular weight of approximately 200 to 900, and the number average molecular weight of the stabilizer (B1) and the weight average molecular weight become substantially the same value. When the stabilizer (B1) and the stabilizer (B2) are used in combination as the stabilizer (B), it is preferred to contain a plurality of stabilizers (B1) from the viewpoint of improving transparency. Specifically, from the viewpoint of coexistence of transparency and moist heat resistance, the stabilizer (B2) is preferably in the range of 10 parts by mass to 150 parts by mass, more preferably 100 parts by mass of the stabilizer (B1). The range of 30 parts by mass to 100 parts by mass is particularly preferably in the range of 50 parts by mass to 100 parts by mass.

The piezoelectric polymer film used in the present embodiment is more preferably composed of a carbodiimide group, an epoxy group, and an isocyanate group, in an amount of 100 parts by mass based on 100 parts by weight of the helical chiral polymer (A). One or more functional groups in the group, and the stabilizer (B) having a weight average molecular weight of 200 to 60,000 is 0.01 parts by mass to 10 parts by mass. More preferably, the piezoelectric polymer film used in the present embodiment has an internal haze of 13% or less with respect to visible light, and 100 parts by mass of the helical chiral polymer (A), and has a selected from the group consisting of carbon two. One or more functional groups in the group consisting of a quinone imine group, an epoxy group, and an isocyanate group, and the stabilizer (B) having a weight average molecular weight of 200 to 60,000 is 0.01 parts by mass to 2.8 parts by mass. Thereby, the piezoelectric piezoelectric film is more excellent in balance of piezoelectricity, transparency, and moist heat resistance.

Specific examples of the stabilizer (B) (stabilizer SS-1 to stabilizer SS-3) are shown below.

[Chemical 3]

Hereinafter, the stabilizer SS-1 to the stabilizer SS-3 are represented by a compound name, a commercially available product, and the like. Stabilizer SS-1... The compound name is bis-2,6-diisopropylphenylcarbodiimide. The weight average molecular weight (in this example, only equivalent to "molecular weight") was 363. As a commercial item, "Stabaxol I" manufactured by Rhein Chemie Co., Ltd., and "B2756" manufactured by Tokyo Chemical Industry Co., Ltd. are mentioned. Stabilizer SS-2... The compound name is poly(4,4'-dicyclohexylmethane carbodiimide). "Carbodilite LA-1" manufactured by Nisshinbo Chemical Co., Ltd., which is a weight average molecular weight of about 2,000, is mentioned as a commercial item. Stabilizer SS-3... The compound name is poly(1,3,5-triisopropylphenylene-2,4-carbodiimide). As a commercial item, "Stabaxol P" manufactured by Rhein Chemie Co., Ltd., which has a weight average molecular weight of about 3,000, is mentioned. In addition, as a weight average molecular weight of 20,000, "Stabaxol P400" by Rhein Chemie Co., Ltd. is mentioned.

(Antioxidant) The piezoelectric polymer film used in the present embodiment may contain an antioxidant. The antioxidant is preferably at least one compound selected from the group consisting of a hindered phenol compound, a hindered amine compound, a phosphite compound, and a thioether compound. Further, as the antioxidant, a hindered phenol compound or a hindered amine compound is more preferably used. Thereby, a polymer piezoelectric film excellent in moisture heat resistance and transparency can be provided.

(Other components) The polymer piezoelectric film used in the present embodiment may contain a known resin typified by polyvinylidene fluoride, polyethylene resin or polystyrene resin, to the extent that the effects of the present invention are not impaired. Or an inorganic filler such as cerium oxide, hydroxyapatite or montmorillonite, or other components such as a known crystal nucleating agent such as phthalocyanine. In addition, when the polymer piezoelectric film contains a component other than the helical chiral polymer (A), the content of the component other than the helical chiral polymer (A) is preferably 20% based on the total mass of the piezoelectric polymer film. The mass% or less is more preferably 10% by mass or less.

The polymer piezoelectric film used in the present embodiment may contain the helical chiral polymer (A) (that is, the weight average molecular weight (Mw) is 50,000 to 100, within the limits of the effects of the present invention. An optically active helical chiral polymer other than the optically active helical chiral polymer (A).

Further, from the viewpoint of transparency, the piezoelectric polymer film preferably contains no components other than the optically active helical chiral polymer (A).

- Method for Producing Polymer Piezoelectric Film - As a method for producing the piezoelectric polymer film used in the present embodiment, the crystallinity can be adjusted to 20% to 80%, and the normalized molecules can be aligned to the MORc and crystallized. There is no particular limitation on the method of adjusting the product of the degree to 40 to 700. This method can be, for example, a method including a step of forming a composition containing a helical chiral polymer (A) into a film shape (forming step), and a step of stretching the formed film (extension step). It is suitably manufactured. For example, the production method described in paragraphs 0065 to 099 of International Publication No. 2013/054918 can be cited.

(Molding step) The molding step is to heat a composition containing other components such as a helical chiral polymer (A) and, if necessary, a stabilizer (B) to a melting point Tm (° C.) or more of the helical chiral polymer (A). The temperature is shaped to form a film shape. By this molding step, a film containing other components such as a helical chiral polymer (A) and, if necessary, a stabilizer (B) can be obtained.

In the present specification, the melting point Tm (° C.) of the helical chiral polymer (A) and the glass transition temperature (Tg) of the helical chiral polymer (A) refer to the use of a differential scanning calorimeter (Differential). Scanning Calorimeter (DSC) is a value obtained by melting the endothermic curve when the temperature of the helical chiral polymer (A) is raised under the conditions of a temperature increase rate of 10 ° C/min. The melting point (Tm) is a value obtained as a peak of an endothermic reaction. The glass transition temperature (Tg) is a value obtained as a critical point of the melting endothermic curve.

The composition can be produced by mixing other components such as a helical chiral polymer (A) and, if necessary, a stabilizer (B). The mixing can also be melt kneading. Specifically, the composition can be produced by adding a component such as a helical chiral polymer (A) and, if necessary, a stabilizer (B) to a melt kneading machine [for example, Toyo Seiki Co., Ltd. In the manufactured Labo mill (Labo Plastomill), it is heated to a temperature equal to or higher than the melting point of the helical chiral polymer (A) to carry out melt kneading. In this case, in the state where the temperature is equal to or higher than the melting point of the helical chiral polymer (A), the temperature is raised to a temperature equal to or higher than the melting point of the helical chiral polymer (A). The composition produced by melt kneading is formed into a film shape. Examples of the conditions for the melt kneading include a mixer rotation speed of 30 rpm to 70 rpm, a temperature of 180 ° C to 250 ° C, and a kneading time of 5 minutes to 20 minutes.

In the present molding step, as a method of forming the composition into a film shape, a melt extrusion molding, press molding, injection molding, calender molding, or a molding method by a casting method is used. Further, it may be formed into a film shape by a T-die extrusion molding method or the like.

When the composition is formed into a film shape by a T-die extrusion molding method, for example, the extrusion temperature is preferably adjusted to 200 to 230 ° C, more preferably to 220 to 230 ° C.

In the forming step, the composition may be heated to the above temperature to form a film, and the obtained film may be rapidly cooled. The crystallinity of the film obtained in this step can be adjusted by rapid cooling. Here, "rapid cooling" means that the glass transition temperature Tg of at least the spiral chiral polymer (A) is cooled at least after the extrusion. In the present embodiment, it is preferred that no other treatment is included between the formation of the film and the rapid cooling.

The method of rapid cooling may be a method of immersing the membrane in water, ice water, ethanol, ethanol or methanol to which dry ice is added, or a refrigerant such as liquid nitrogen; and blowing a liquid spray having a low vapor pressure on the membrane by evaporating latent heat A method in which a film is cooled, and the like.

In addition, in order to continuously cool the film, the metal roll which is at a temperature lower than the glass transition temperature Tg of the helical chiral polymer (A) may be brought into contact with the film or the like to perform rapid cooling. In addition, the number of times of cooling may be only one time, or may be two or more times.

The film obtained by the molding step (that is, the film to be subjected to the stretching step described later) may be an amorphous film or a pre-crystallized film (hereinafter also referred to as "pre-crystallized film"). . Here, the film in an amorphous state means a film having a crystallinity of less than 3%. In addition, the pre-crystallized film means a film having a crystallinity of 3% or more (preferably 3% to 70%). Here, the degree of crystallinity refers to a value measured by the same method as the crystallinity of the polymer piezoelectric film.

The thickness of the film (the amorphous state film or the pre-crystallized film) obtained by the molding step is mainly determined depending on the thickness and the stretching ratio of the finally obtained polymer piezoelectric film, but is preferably 50 μm to 1000. Μm, more preferably from about 100 μm to about 800 μm.

The pre-crystallized film can be obtained by crystallization of a film in an amorphous state containing other components such as a helical chiral polymer (A) and, if necessary, a stabilizer (B). The heating temperature T for pre-crystallization of the film in an amorphous state is not particularly limited, but from the viewpoint of improving the piezoelectricity or transparency of the produced piezoelectric polymer film, etc., it is preferable to The glass transition temperature Tg of the helical chiral polymer (A) satisfies the relationship of the following formula, and the crystallinity is set to be 3% to 70%. Tg-40°C≦T≦Tg+40°C (Tg represents the glass transition temperature of the helical chiral polymer (A))

The heating time for pre-crystallizing the film in an amorphous state can be appropriately set in consideration of the normalized molecular alignment MORc or crystallinity of the polymer piezoelectric film finally obtained. The heating time is preferably from 5 seconds to 60 minutes. There is a tendency that the normalized molecular alignment MORc becomes higher as the heating time becomes longer, and the crystallinity becomes higher. For example, when a film containing an amorphous state of the polylactic acid-based polymer as the helical chiral polymer (A) is precrystallized, it is preferably heated at 20 to 170 ° C for 5 seconds to 60 minutes.

When the film in the amorphous state is pre-crystallized, for example, a casting roll adjusted to the above temperature range can be used. The polymer piezoelectric film can be adhered to the casting roll for precrystallization by the electrostatic adhesion method to perform precrystallization, and the peak of the thickness can be adjusted. For example, when a wire for adhering the entire surface of the film is used, the peak of the thickness can be adjusted by the adjustment of the position of the electrode, the material, the applied voltage, and the like.

(Extension Step) The stretching step is a step of stretching the film (for example, the pre-crystallized film) obtained in the forming step mainly in the uniaxial direction. By this step, a polymer piezoelectric film having a large main surface area can be obtained as a stretched film. In addition, the large area of the principal surface means that the area of the principal surface of the piezoelectric polymer film is 5 mm ² or more. Further, the area of the main surface is preferably 10 mm ² or more.

In addition, it is estimated that the molecular chain of the helical chiral polymer (A) contained in the film can be aligned in one direction and arranged at a high density by stretching the film mainly in the uniaxial direction. Higher piezoelectricity. As a method of extending in a uniaxial direction by using a continuous process, the longitudinal direction of the forward direction (MD direction) of the process may be the same as the extending direction, or may be the direction (TD direction) and the extending direction perpendicular to the advancing direction of the process. Consistent lateral extension.

When the film is stretched only by the stretching force as extending in the uniaxial direction, the film extending temperature is preferably higher than the glass transition temperature of the film (or the spiral chiral polymer (A) in the film). A temperature range of about 10 ° C to 20 ° C.

The stretching ratio (main stretching ratio) in the stretching treatment is preferably 2 to 10 times, more preferably 3 to 5 times, still more preferably 3 to 4 times. Thereby, a polymer piezoelectric film having higher piezoelectricity and transparency can be obtained.

Further, in the extending step, when the extension (main extension) for improving the piezoelectricity is performed, the forming may be simultaneously or sequentially formed in a direction crossing (preferably orthogonal) to the direction of the main extension. The film obtained in the step (for example, a pre-crystallized film) is extended (also referred to as a sub-extension). In addition, the "sequential extension" as used herein refers to an extension method of extending in a direction crossing the extending direction after first extending in the uniaxial direction. When the sub-stretching is performed in the stretching step, the stretching ratio of the sub-stretching is preferably from 1 to 3 times, more preferably from 1.1 to 2.5 times, still more preferably from 1.2 to 2.0 times. Thereby, the tear strength of the piezoelectric polymer film can be further improved.

When the extension of the pre-crystallized film is carried out in the stretching step, preheating may be performed just before the extension in order to facilitate the stretching of the film. This preheating is usually carried out in order to soften the film before stretching and to easily extend it. Therefore, it is usually carried out under conditions which do not crystallize the film before stretching and harden the film. However, as described above, in the present embodiment, pre-crystallization may be performed before stretching, and the preheating may be performed as a pre-crystallization. Specifically, the heating temperature or the heat treatment time in the precrystallization step is preheated at a temperature higher than the temperature in the usual process or for a longer period of time, thereby allowing for both preheating and precrystallization.

(Annealing Step) The production method of the present embodiment may have an annealing step as needed. The annealing step is a step of annealing (heat treatment) the film (hereinafter, also referred to as "stretch film") which is extended in the stretching step. By the annealing step, the crystallization of the stretched film can be further progressed, and a piezoelectric piezoelectric film having higher piezoelectricity can be obtained. Further, when the stretched film is mainly crystallized by annealing, the operation of pre-crystallization in the forming step may be omitted. In this case, as the film obtained by the forming step (that is, the film to be supplied to the stretching step), a film in an amorphous state can be selected.

In the present embodiment, the annealing temperature is preferably from 80 ° C to 160 ° C, more preferably from 100 ° C to 155 ° C.

The method of annealing (heat treatment) is not particularly limited, and a method of directly heating the stretched film by contact with a heating roller, a hot air heater or an infrared heater; by immersing the stretched film in heating A method of heating in a liquid (such as eucalyptus oil).

The annealing is preferably performed by applying a predetermined tensile stress (for example, 0.01 MPa to 100 MPa) to the stretched film without loosening the stretched film.

The annealing time is preferably from 1 second to 5 minutes, more preferably from 5 seconds to 3 minutes, still more preferably from 10 seconds to 2 minutes. When the annealing time is 5 minutes or less, the productivity is excellent. On the other hand, if the annealing time is 1 second or longer, the crystallinity of the film can be further increased.

The annealed stretched film (i.e., the polymer piezoelectric film) is preferably subjected to rapid cooling after annealing. The "rapid cooling" performed in the annealing step may be the same as the "rapid cooling" which may be performed in the molding step described above. The number of times of cooling may be only one time, or may be two or more times, and further, annealing and cooling may be alternately repeated.

[Functional Layer (X)] The functional layer (X) is a layer provided on at least one main surface of the piezoelectric polymer film. The functional layer (X) functions as a layer for protecting the piezoelectric film of the polymer, a layer for bonding the other layer to the piezoelectric film of the polymer, and the like. The functional layer (X) is preferably in contact with the polymer piezoelectric film.

As the functional layer (X), a bonding layer is preferred. Furthermore, in this specification, "subsequent" is a concept that includes adhesion, and "adhesive layer" also includes an adhesive layer. Hereinafter, an adhesive layer which is one form of the functional layer (X) will be described.

Next, the layer is a layer having an adhesive property, and as the adhesive layer, a double-sided tape (Optical Clear Adhesive (OCA)) in which both faces are laminated by a spacer can be used. Further, the adhesive layer may be formed by using an adhesive coating liquid such as a solvent system, a solventless system or an aqueous system, an ultraviolet (UV) curing optical transparent resin (OCR), a hot melt adhesive or the like. .

As the OCA, the transparent adhesive sheet for optical use LUCIACS series (manufactured by Nitto Denko Corporation) or the high transparent double-sided tape 5400A series (manufactured by Sekisui Chemical Co., Ltd.) and the optical adhesive sheet Opteria series (Lintec) )), a highly transparent adhesive transfer tape series (manufactured by Sumitomo 3M Co., Ltd.), SANCUARY series (manufactured by Sun A. Kaken Co., Ltd.), and the like.

Examples of the adhesive coating liquid (the coating liquid) include SK-Dyne series (manufactured by Synthetic Chemical Co., Ltd.), Finetec series (manufactured by Dickson Co., Ltd.), Voncoat series, and LKG series (Fujikura Kasei Co., Ltd. manufactured by Co., Ltd., Corponiel series (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.).

As the adhesive layer, from the viewpoint of preventing heating of the piezoelectric polymer film, an adhesive layer of OCA, an adhesive layer formed using OCR, and a member other than the polymer piezoelectric film coated with the adhesive coating liquid are preferable. An adhesive layer formed on (for example, a release film to be described later) and a thermal-melting adhesive are used for the adhesive layer formed of a member other than the polymer piezoelectric film.

The material of the adhesive layer is not particularly limited, but preferably contains a resin. Examples of the resin include an acrylic resin, a methacrylic resin, a urethane resin, a cellulose resin, a vinyl acetate resin, an ethylene-vinyl acetate resin, an epoxy resin, and a nylon. - epoxy resin, vinyl chloride resin, chloroprene rubber resin, cyanoacrylate resin, fluorenone resin, modified fluorenone resin, aqueous polymer - isocyanate resin, styrene - butyl Diene rubber resin, nitrile rubber resin, acetal resin, phenol resin, polyamide resin, polyimide resin, melamine resin, urea resin, bromine resin, starch resin, polyester resin, polyolefin resin, etc. .

The thickness of the functional layer (X) is not particularly limited. However, from the viewpoint of suppressing the maintenance of the adhesion between the functional layer (X) and the decrease in the transmittance, the thickness is preferably 5 μm or more, and more preferably It is set to 7 μm to 100 μm, more preferably 7 μm to 60 μm, and particularly preferably 10 μm to 30 μm.

- Acid value of the functional layer (X) - The acid value of the functional layer (X) is preferably 10 mgKOH/g or less, more preferably 5 mgKOH/g or less, from the viewpoint of suppressing deterioration of the laminated film in a hot and humid environment. More preferably, it is 1 mgKOH/g or less. The acid value of the functional layer (X) is preferably 0.01 mgKOH/g or more, more preferably 0.05 mgKOH/g or more, from the viewpoint of further improving the adhesion between the polymer piezoelectric film and the functional layer (X). Preferably it is 0.1 mgKOH/g or more. In the present specification, the acid value of the functional layer (X) means the amount (mg) of KOH required to neutralize the free acid in 1 g of the functional layer (X). The amount (mg) of the KOH was measured by using phenolphthalein as an indicator, and titrating the functional layer (X) dissolved or swollen in a solvent by a 0.005 M KOH (potassium hydroxide) ethanol solution.

The total nitrogen content of the functional layer (X) is preferably from 0.05% by mass to 10% by mass, more preferably from 0.2% by mass to 5% by mass. Thereby, the heat resistance of the aliphatic polyester polymer piezoelectric film is improved.

[Other Layers] In the film roll layer of the present embodiment, the build-up film may have another layer between the polymer piezoelectric film and the functional layer (X). Examples of the other layer include an easy adhesion layer, a hard coat layer, a refractive index adjusting layer, an antireflection layer, an antiglare layer, a slip layer, an anti-blocking layer, a protective layer, an antistatic layer, a heat dissipation layer, and ultraviolet absorption. Layer, anti-Newton ring layer, light scattering layer, polarizing layer, gas barrier layer, hue adjustment layer, and the like. Further, as the other layer, two or more layers of the functions of the other layers may be combined, and two or more layers may be laminated in this order. Among these, as the other layer, at least one of a refractive index adjusting layer, an easy-adhesion layer, a hard coat layer, an antistatic layer, and an anti-blocking layer is preferable. When other layers are provided on the two main surface sides of the piezoelectric polymer film, the two other layers may be the same layer or different layers.

The material of the other layer is not particularly limited, and examples thereof include an inorganic substance such as a metal or a metal oxide, an organic substance such as a resin, and a composite composition containing a resin and fine particles. As the resin, for example, a cured product obtained by curing by temperature or an active energy ray can also be used. That is, as the resin, a curable resin can also be used.

The curable resin is, for example, selected from the group consisting of an acrylic compound, a methacrylic compound, a vinyl compound, an allyl compound, a urethane compound, an epoxy compound, and an epoxide compound. , a glycidyl compound, an oxetane compound, a melamine compound, a cellulose compound, an ester compound, a decane compound, an anthrone compound, a siloxane compound, a cerium oxide-acrylic compound And at least one material (curable resin) of the group consisting of cerium oxide-epoxy resin mixed compounds. Among these, an acrylic compound, an epoxy compound, and a decane compound are more preferable. Examples of the metal include, for example, Al, Si, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, In, Sn, W, Ag, Au, Pd, Pt, Sb, Ta, and Zr. At least one, or alloy of the same. Examples of the metal oxide include titanium oxide, zirconium oxide, zinc oxide, cerium oxide, cerium oxide, tin oxide, indium oxide, cerium oxide, aluminum oxide, cerium oxide, magnesium oxide, cerium oxide, cerium oxide, and oxidation. At least one of cerium, and a composite oxide thereof. Examples of the fine particles include fine particles of a metal oxide as described above, resin fine particles such as a fluorine resin, an anthrone resin, a styrene resin, and an acrylic resin. Further, hollow fine particles having pores inside the fine particles may be mentioned. The average primary particle diameter of the fine particles is preferably 1 nm or more and 500 nm or less, more preferably 5 nm or more and 300 nm or less, and still more preferably 10 nm or more and 200 nm or less from the viewpoint of transparency. By 500 nm or less, scattering of visible light is suppressed, and secondary aggregation of fine particles is suppressed by 1 nm or more, and it is preferable from the viewpoint of maintaining transparency.

The film thickness of the other layer is not particularly limited, but is preferably in the range of 0.01 μm to 10 μm. The upper limit of the thickness is more preferably 6 μm or less, and still more preferably 3 μm or less. Further, the lower limit value is more preferably 0.2 μm or more, and still more preferably 0.3 μm or more. However, in the case where the other layer is a multilayer film including a plurality of layers, the thickness indicates the thickness of the entire multilayer film.

By forming other layers, defects such as mold lines or bumps on the surface of the piezoelectric film of the polymer are compensated, and the appearance is improved. In this case, the smaller the refractive index difference between the polymer piezoelectric film and the other layers, the smaller the reflection between the polymer piezoelectric film and the other layers and the interface, and the appearance is further improved.

As a method of forming the other layer, a known method which has been conventionally used can be suitably used, and examples thereof include a vapor deposition method, a sputtering method, an ion plating method, and a chemical vapor deposition (Chemical Vapor Deposition). Dry coating method such as CVD)) method, plating method, wet coating method. Examples of the wet coating method include a roll coating method, a spin coating method, a dip coating method, a bar coating method, and a gravure coating method. For example, when another layer is formed from a curable resin, another layer is formed by coating a coating liquid in which a material containing a curable resin, an additive, a solvent, or the like is dispersed or dissolved.

Further, the material (curable resin or the like) coated as described above may be volatilized by drying or by heat or active energy rays (ultraviolet rays, electron beams, radiation, etc.). Irradiation to harden the curable resin.

Further, among the curable resins, an active energy ray-curable resin which is cured by irradiation with an active energy ray (ultraviolet rays, electron beams, radiation, or the like) is preferable. By including the active energy ray-curing resin, the production efficiency is improved, and the performance deterioration of the polymer piezoelectric film caused by the formation of the other layers can be further suppressed.

Further, when the other layer is formed from a curable resin, the other layer preferably contains a three-dimensional crosslinked resin having a three-dimensional crosslinked structure from the viewpoint of increasing the crosslinking density.

The method of producing a cured product having a three-dimensional crosslinked structure includes a method of using a monomer having three or more polymerizable functional groups (a trifunctional or higher monomer) as a curable resin, and a method of using three or more polymerizations. A method of using a functional group-based crosslinking agent (trifunctional or higher crosslinking agent), and the like, and a method using a crosslinking agent such as an organic peroxide as a crosslinking agent. Furthermore, a plurality of combinations of the methods may be used.

Examples of the trifunctional or higher monomer include a (meth)acrylic compound having three or more (meth)acrylic groups in one molecule, or an epoxy compound having three or more epoxy groups in one molecule. Wait.

In addition, the term "having three or more (meth)acrylic groups in one molecule" means at least one of an acrylic group and a methacrylic group in one molecule, and an acrylic group and a methacrylic group in one molecule. The total number is more than three.

Here, as a method of confirming whether or not the material contained in the other layer is a cured product having a three-dimensional crosslinked structure, a method of measuring the gel fraction is exemplified. Specifically, the gel fraction can be derived from the insoluble matter after the other layer is immersed in the solvent for 24 hours. In particular, it can be inferred that the solvent is a hydrophilic solvent such as water or a lipophilic solvent such as toluene, and the gel fraction is a certain amount or more and has a three-dimensional crosslinked structure.

In the case of the wet coating method, the coating liquid can be applied to the pre-extended original film of the piezoelectric polymer film to extend the polymer piezoelectric film, or the polymer piezoelectric film can be used. The coating liquid was applied after the stretching. The thickness of the (one layer) of the other layer formed by the wet coating method is preferably in the range of several tens of nm to 10 μm. Further, various organic substances and inorganic substances such as a refractive index adjusting agent, an ultraviolet absorber, a leveling agent, an antistatic agent, and an anti-blocking agent may be added to other layers in accordance with the purpose. Further, from the viewpoint of improving the adhesion between the surface of the piezoelectric polymer film and other layers, or improving the coating property on the surface of the piezoelectric polymer film, corona treatment, ITRO treatment, ozone treatment, The surface of the polymer piezoelectric film is treated by plasma treatment or the like.

[Release film] In the film roll layer of the present embodiment, the build-up film preferably has a mold release disposed on the side opposite to the side on which the polymer piezoelectric film is disposed, as viewed from the functional layer (X). membrane. The film roll layer of the present embodiment is obtained by winding a laminated film having a polymer piezoelectric film, a functional layer (X), and a release film into a roll shape, and the laminated film preferably has a length in the MD direction. More than 10 m.

As the material of the release film, a material having mold release property (peelability) can be suitably used. The release film may be a separate film or a multilayer film comprising a plurality of layers. When the release film is a multilayer film including a plurality of layers, the release film is preferably formed to have a material having mold release property on a surface facing the adhesive layer. In this case, the release film may be formed into a structure including a substrate and a material having mold release properties.

Specific examples of the material having releasability include polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polyethylene, polypropylene, and the like. Olefin resin such as polymethylpentene; fluororesin such as polytetrafluoroethylene or polyvinylidene fluoride; polyvinyl chloride, styrene (meth)acrylic acid copolymer, styrene (meth) acrylate copolymer, polyphenylene A vinyl resin such as ethylene or ethylene-vinyl acetate. Further, as the material having mold release property, in addition to the above, examples thereof include a polyurethane resin, a polyimide resin, a polyamide resin, an anthrone resin, an acrylic resin, a melamine resin, and the like. Alkyd resin, wax resin, and the like. The release film may be a separate film of these or a multilayer film comprising a plurality of layers. In this case, the release film is preferably formed to have a material having mold release property on a surface facing the adhesive layer. Among them, from the viewpoint of further improving the releasability from the adhesive layer, it is more preferable to use a material having mold release property on the surface facing the adhesive layer to use an fluorenone resin, a fluororesin, a polyester resin, or a polyolefin. A resin, an alkyd resin, a wax resin, and more preferably an anthrone resin.

Examples of the fluorenone resin include a terminal stanol-functional dimethyl polyoxyalkylene and methyl hydrogen polyoxy siloxane or methyl methoxy decane in the presence of an organotin-based catalyst. The reaction is carried out (thermal condensation reaction type); in the presence of a platinum-based catalyst, methyl vinyl polyoxyalkylene having a vinyl group at both ends or both ends of the molecular chain and a side chain, and methyl hydrogen A polysiloxane is used for the reaction (thermal addition reaction type); a photopolymerization agent is added to a decyl alkane containing an alkenyl group and a mercapto group (ultraviolet curing type (radical addition molding)); use and heat A platinum-based catalyst having the same addition reaction type (ultraviolet curing type (hydrogenated alkylene group)); a photopolymerization agent added to a (meth)acrylic group-containing oxirane (ultraviolet curing type (free radical) Polymerized)); a sulfonium salt photoinitiator added to an epoxy group-containing oxirane (ultraviolet curing type (cationic polymerization type)); a radical polymerizable group-containing oxime (electron beam hardening) a type in which a functional group is not present, and Photoinitiator). Further, the form of the fluorenone resin can be appropriately selected from the group consisting of a solvent type, an emulsion type, and a solventless type.

[Substrate] When the release film is formed into a structure including a substrate and a material having mold release properties, examples of the substrate include polyethylene terephthalate, polyethylene naphthalate, and polybutylene. Butylene phthalate, polyethylene, polypropylene, polymethylpentene, triacetyl cellulose, cellophane, hydrazine, polystyrene, polycarbonate, polyimine, polyamine, Examples of the polyphenylene sulfide, the polyether quinone, the polyether fluorene, the aromatic polyamine, or the polyfluorene resin include uniaxially stretched films, biaxially stretched films, nonwoven fabrics, and foams. Further, the substrate may be selected from glass, metal foil, ceramics, paper, and the like.

In the release film, a layer containing another material such as an antistatic agent, an oligomer transfer inhibitor, a smoothing agent, or an easy adhesive may be provided on a layer other than the surface facing the adhesive layer as needed. For example, when the release film is formed into a structure including a substrate and a material having mold release property, the surface of the substrate and the material having the release property and the release property of the substrate can be released. A layer comprising the other material is disposed on the face of either or both of the opposing faces of the material.

The film thickness of the release film is not particularly limited, but is preferably in the range of 5 μm or more, more preferably in the range of 10 μm to 100 μm, and still more preferably 20 in terms of ease of release and handling. The range of μm to 80 μm is particularly preferably in the range of 30 μm to 80 μm.

In order to suitably peel off the release film, it is preferred that the adhesion of the adhesive layer to the polymer piezoelectric film is greater than the adhesion of the adhesive layer to the release film.

As a method of forming the release film, a known method which has been conventionally used can be suitably used. For example, the release film can be formed by extrusion-forming a resin forming a release film by a film forming machine. When the release film is a multilayer film including a plurality of layers, each of the film-formed release films may be formed into a plurality of layers by an adhesive, or may be formed into a plurality of layers by co-extrusion film formation using a multilayer film forming machine. . Further, when the release film is a multilayer film including a plurality of layers including a structure of a substrate and a material having mold releasability, the film-formed substrate and the film-formed film can be formed by an adhesive agent. The release material is formed into a plurality of layers, and the material having mold release property may be extrusion-molded on the film-formed substrate to form a plurality of layers, or a material of the substrate may be formed by using a multilayer film machine. The release material is coextruded to form a film.

Further, it can also be formed by a wet coating method. For example, when a release film is formed by a wet coating method, a coating liquid (a release coating film) for dissolving or dissolving a material (resin, additive, etc.) which is useful for forming a release film can be used. ) is formed by coating on the adhesive layer. Further, when the release film is a multilayer film including a plurality of layers including a substrate and a material having a release property, it can be formed by applying a coating liquid for a release film onto a substrate.

When a material having mold release property is formed by a wet coating method, the material having mold release property can be used as a coating liquid such as a solution or an emulsion, and can be coated by a roll coater or a notch wheel. A known method such as a machine, a die coater, a Meyer bar coater, a reverse roll coater, or a gravure coater is applied to an adhesive layer or a substrate and dried. Further, when the release film is a multilayer film including a plurality of layers, the surface of the release film opposite to the surface facing the adhesive layer or the surface of the release film facing the adhesive layer may be The base material of the surface on the opposite side is subjected to surface activation treatment such as corona discharge treatment, flame treatment, ozone treatment, or tackifying coating treatment using a tackifier. The adhesion of the multilayer film is enhanced by such treatment, so that the release property from the adhesive layer can be further improved.

<Method for Producing Film Reel Body> Hereinafter, an embodiment of the method for producing a film reel body of the present invention will be described. Examples of the method for producing the film roll layer include a method of forming a functional layer (X) on a release film, and bonding the functional layer (X) and the polymer piezoelectric film to form a film roll layer; A method of forming a functional layer (X) on a polymer piezoelectric film, bonding a functional layer (X) to a release film, and forming a film roll layer.

[First Embodiment] A method for producing a film roll layer body according to the first embodiment includes applying a functional layer forming agent for forming a functional layer (X) to a main surface of a release film to form a functional layer (X). a step of forming a laminated film by bonding a functional layer (X) and a piezoelectric polymer film on the side opposite to the side on which the release film is disposed, as viewed from the functional layer (X); and forming the laminated film The step of winding the laminated film into a roll shape. In the manufacturing method, the functional layer (X) formed on the release film is bonded to the piezoelectric polymer film to form a laminated film, and the formed laminated film is wound into a roll to produce a film wound body. .

- Formation of Functional Layer (X) - The method for producing a film wound layer according to the present embodiment includes applying a functional layer forming agent for forming the functional layer (X) to the main surface of the release film to form a functional layer (X) A step of. In this case, a film-like or sheet-like material (for example, the OCA) may be applied as a functional layer forming agent to the main surface of the release film to form the functional layer (X), or a liquid functional layer forming agent may be used. (for example, an adhesive coating liquid) is applied to the main surface of the release film, and the functional layer forming agent to be applied is dried to form a functional layer (X). At this time, the drying temperature of the functional layer forming agent is preferably from 50 ° C to 150 ° C, more preferably from 70 ° C to 130 ° C. Further, when the functional layer (X) is applied to the main surface of the release film, a coating device can also be used.

Here, as the functional layer (X), a bonding layer is preferable, and as a functional layer forming agent, an adhesive is preferable. Therefore, an adhesive may be applied to the main surface of the release film to form an adhesive layer. Examples of the adhesive agent include an OCA, a solvent-based, solvent-free, water-based adhesive coating liquid, a UV-curable OCR, and a hot-melt adhesive.

- Formation of laminated film - As described above, after the formation of the functional layer (X), the method for producing the laminated film of the present embodiment includes the opposite to the side on which the release film is disposed, as viewed from the functional layer (X). On one side, a step of laminating the functional layer (X) and the piezoelectric polymer film to form a laminated film. As a result, a laminated film of a polymer piezoelectric film, a functional layer (X), and a release film can be sequentially laminated in the vertical direction of the main surface of the piezoelectric polymer film.

Further, the functional layer (X) may be formed on the main surface of the other release film, and the functional layer may be formed on the side opposite to the side on which the release film is disposed as viewed from the functional layer (X). X) is bonded to a polymer piezoelectric film constituting a three-layer laminated film formed as described above. Thereby, the release film, the functional layer (X), the polymer piezoelectric film, the functional layer (X), and the release film can be laminated in the vertical direction of the main surface of the piezoelectric polymer film. Laminated film.

Further, the polymer piezoelectric film used for forming the buildup film may be provided with the other layer on at least one main surface. Thereby, when a laminated film is formed, another layer is disposed between the functional layer (X) and the polymer piezoelectric film.

- Manufacture of Film Reel Body - The method for producing a film reel body of the present embodiment includes a step of winding the formed laminated film into a roll shape. Thereby, a roll-shaped film wrap layer can be obtained. In the manufacturing method of the present embodiment, the functional layer (X) is not formed on the polymer piezoelectric film, but the functional layer (X) is formed on the release film, and the functional layer (X) formed is high. The molecular piezoelectric film is bonded. Therefore, it is not necessary to heat the piezoelectric polymer film, and the occurrence of stretching in the polymer piezoelectric film is suppressed. As a result, the dimensional change rate measured in the above manner can be set to 1.0% or less in the MD direction. Further, since the film roll layer obtained by the production method of the present embodiment has high dimensional stability, the occurrence of cracks in the polymer piezoelectric film during heating is suppressed, and the heat resistance of the polymer piezoelectric film is suppressed. Excellent sex.

Hereinafter, an example of a method of producing a film wrap by a continuous process of a roll-to-roller will be described with reference to FIG. Fig. 1 is a schematic view showing a method of producing a film roll layer by forming an adhesive layer on a release film in the first embodiment of the present invention.

First, in the film roll layer production apparatus 10, the release film 2 is taken out from the roll-shaped release film 1 fixed to the roll body, and the extracted release film 2 is taken up by the other roll body. Further, the adhesive 3 is applied onto the release film 2 between the rolls using the coating device 8. After the adhesive 3 is applied onto the release film 2, the adhesive 3 is dried by a drying mechanism (drying furnace) 9, and the adhesive layer 4 is formed on the main surface of the release film 2.

In addition, the piezoelectric polymer film 6 is taken out from the roll-shaped polymer piezoelectric film 5 fixed to the roll body, and the extracted polymer piezoelectric film 6 is bonded to the release film 2, and then released from the release film. 2 is taken together by the roller body. Therefore, when the adhesive layer 4 is formed on the main surface of the release film 2, the adhesive layer is formed by bonding the adhesive layer 4 to the polymer piezoelectric film 6. Further, the film laminated body 7 can be obtained by winding the formed laminated film into a roll shape.

In the continuous process of the roll-to-roll, tension is generated in the film between the rolls in the advancing direction (MD direction) of the film. Therefore, when a piezoelectric polymer film containing an aliphatic polyester such as polylactic acid is placed between rolls, and heat is applied to the polymer piezoelectric film when the adhesive layer is formed, heat resistance of the polymer piezoelectric film is caused. Since the properties are low, stretching occurs in the piezoelectric polymer film due to the generated tension, and the dimensional stability of the polymer piezoelectric film is deteriorated.

On the other hand, in the continuous process of the roll-to-roll as shown in Fig. 1, since the adhesive layer is formed on the release film, it is not necessary to apply heat to the polymer piezoelectric film. Therefore, the stretching of the polymer piezoelectric film is suppressed, and the dimensional stability of the polymer piezoelectric film can be maintained.

[Second Embodiment] Next, a method of manufacturing the film wound layer body of the second embodiment will be described. In addition, the description of the matter common to the first embodiment will be omitted. The method for producing a film roll layer body according to the second embodiment includes applying a functional layer forming agent for forming the functional layer (X) to at least one main surface of the polymer piezoelectric film, and a step of drying the applied functional layer forming agent to form the functional layer (X) at a temperature lower than ° C; opposite to the side on which the piezoelectric film is disposed, as viewed from the functional layer (X) One side, a step of bonding the functional layer (X) to the release film to form the laminated film, and a step of winding the formed laminated film into a roll shape. In the production method, the functional layer forming agent is dried at a temperature of 90 ° C or lower to form the functional layer (X) on the piezoelectric polymer film, and then the functional layer (X) formed on the piezoelectric film of the polymer is formed. The laminated film is formed by laminating with a release film, and the formed laminated film is wound into a roll shape, and a film roll body is manufactured.

- Formation of Functional Layer (X) - The method for producing a film wound layer according to the present embodiment includes applying a functional layer forming agent for forming a functional layer (X) on at least one main surface of the piezoelectric polymer film. The step of forming the functional layer (X) by drying the applied functional layer forming agent at a temperature of 90 ° C or lower. At this time, the drying temperature of the functional layer forming agent is preferably from 50 ° C to 90 ° C, more preferably from 60 ° C to 80 ° C. Thereby, the dimensional stability of the polymer piezoelectric film can be more suitably maintained.

Here, as the functional layer (X), a bonding layer is preferable, and as a functional layer forming agent, an adhesive is preferable. Therefore, an adhesive may be applied to the main surface of the piezoelectric polymer film to form an adhesive layer. Examples of the adhesive agent include an OCA, a solvent-based, solvent-free, water-based adhesive coating liquid, a UV-curable OCR, and a hot-melt adhesive.

- Formation of laminated film - As described above, after the formation of the functional layer (X), the method for producing the laminated film includes the side of the functional layer (X) and the side on which the piezoelectric film is disposed. On the opposite side, a step of bonding the functional layer (X) to the release film to form a laminated film. When the functional layer (X) is formed on one main surface of the piezoelectric polymer film, the polymer piezoelectric film and the functional layer (X) are sequentially laminated in the vertical direction of the main surface of the piezoelectric polymer film. And a three-layer laminated film of the release film. When the functional layer (X) is formed on the two main surfaces of the piezoelectric polymer film, a release film, a functional layer (X), and a functional layer (X) are sequentially laminated in the vertical direction of the main surface of the piezoelectric polymer film. A five-layer laminated film of a polymer piezoelectric film, a functional layer (X), and a release film.

- Manufacture of Film Reel Body - The method for producing a film reel body of the present embodiment includes a step of winding the formed laminated film into a roll shape. Thereby, a roll-shaped film wrap layer can be obtained. In the production method of the present embodiment, when the functional layer (X) is formed on the piezoelectric polymer film, the functional layer forming agent on the piezoelectric polymer film is dried at a temperature of 90 ° C or lower. Therefore, the stretching of the polymer piezoelectric film is suppressed as compared with the case where the functional layer forming agent on the piezoelectric polymer film is dried at a temperature exceeding 90 ° C to form the functional layer (X). As a result, the dimensional change rate measured in the above manner can be set to 1.0% or less in the MD direction. Further, since the film roll layer obtained by the production method of the present embodiment has high dimensional stability, the occurrence of cracks in the polymer piezoelectric film during heating is suppressed, and the heat resistance of the polymer piezoelectric film is suppressed. Excellent sex.

Hereinafter, an example of a method of producing a film corrugated body by a continuous process of a roll-to-roller will be described with reference to FIG. 2 is a schematic view showing a method of producing a film roll layer by forming an adhesive layer on a release film in the second embodiment of the present invention.

First, in the film roll layer manufacturing apparatus 20, the polymer piezoelectric film 12 is taken out from the roll-shaped polymer piezoelectric film 11 fixed to the roll body, and the extracted polymer pressure is taken up by the other roll body. Electrical film 12. Further, the adhesive 13 is applied onto the piezoelectric polymer film 12 between the rolls by using the coating device 18. After the adhesive 13 is applied onto the polymer piezoelectric film 12, the adhesive 13 is dried by a drying means (drying furnace) 19 at a temperature of 90 ° C or lower, and is applied to the main surface of the piezoelectric polymer film 12. An adhesive layer 14 is formed thereon.

Further, the release film 16 is taken out from the roll-shaped release film 15 fixed to the roll body, and the extracted release film 16 is bonded to the polymer piezoelectric film 12, and the polymer piezoelectric film 12 is Roller coiling. Therefore, when the adhesive layer 14 is formed on the main surface of the piezoelectric polymer film 12, the adhesive layer 16 is bonded to the release film 16 to form a laminated film. Further, the film laminated body 17 can be obtained by winding the formed laminated film into a roll shape.

In the continuous process of the roll-to-roll, tension is generated in the film between the rolls in the advancing direction (MD direction) of the film. Therefore, when a piezoelectric polymer film containing an aliphatic polyester such as polylactic acid is placed between rolls, and heat is applied to the polymer piezoelectric film when the adhesive layer is formed, heat resistance of the polymer piezoelectric film is caused. Since the properties are low, stretching occurs in the piezoelectric polymer film due to the applied heat, and the dimensional stability of the piezoelectric polymer film is deteriorated.

On the other hand, in the continuous process of the roll-to-roll process of the present embodiment, since the drying temperature of the adhesive when the adhesive layer is formed on the polymer piezoelectric film is 90 ° C or lower, the piezoelectric film of the polymer The stretching is suppressed, and the dimensional stability of the polymer piezoelectric film can be maintained.

<Uses of film roll layer> Film roll body can be used for speakers, headphones, touch panels, remote controls, microphones, underwater microphones, ultrasonic transducers, ultrasonic application measuring instruments, piezoelectric Oscillator, mechanical filter, piezoelectric transformer, delay device, sensor, acceleration sensor, impact sensor, vibration sensor, pressure sensor, touch sensor, electric field sensor, Sound pressure sensors, displays, fans, pumps, variable focus mirrors, soundproofing materials, soundproofing materials, keyboards, audio equipment, information processing machines, measuring machines, medical machines, etc., can be used in components In terms of the sensor sensitivity being maintained high, it is particularly advantageous to utilize a film roll layer in the field of various sensors. In addition, the film roll layer body can also be used as a touch panel combined with a display device. As the display device, for example, a liquid crystal panel, an organic electroluminescence (EL) panel, or the like can be used. Further, the film roll layer body can also be used as a pressure sensitive sensor in combination with another type of touch panel (position detecting member). Examples of the detection method of the position detecting member include an anti-film method, a capacitance method, a surface elastic wave method, an infrared method, and an optical method. [Examples]

Hereinafter, the film wound layer body of the present invention will be more specifically described by way of examples, but the present invention is not limited to the following examples as long as the scope of the invention is not exceeded.

<Production Example 1: Preparation of polymer piezoelectric film> As a helical chiral polymer (A), polylactic acid (PLA) manufactured by Natchi Walker Co., Ltd. was prepared (product name: Ingeo ^TM biopolymer, trademark: 4032D, weight The average molecular weight Mw: 200,000, and 1 part by mass of the following additive X (stabilizer (B)) was added to 99 parts by mass of the polylactic acid, and dry blending was carried out to prepare a raw material. The prepared raw materials were placed in an extruder hopper, and extruded from a T-shaped mold while being heated to 220 ° C to 230 ° C, and contacted with a casting roll at 50 ° C for 0.5 minutes to pre-crystallize the thickness of 150 μm. The film is formed into a film (forming step). The crystallinity of the obtained precrystallized film was measured and found to be 4.91%. The obtained pre-crystallized film was heated to 70 ° C while being stretched by a roll-to-roll roll at an elongation speed of 1,650 mm/min, and uniaxially stretched to 3.5 times in the MD direction to obtain a uniaxially stretched film ( Extension step). Thereafter, the uniaxially stretched film was brought into contact with a roll heated to 130 ° C for 78 seconds by a roll-to-roller to perform annealing treatment (annealing step), and was rapidly cooled by a roll set to 50 ° C, and further wound into a roll. In this manner, a polymer piezoelectric film is obtained.

- Additive X (stabilizer (B)) - As the additive X, a mixture of Stabaxol I (70 parts by mass) manufactured by Rhein Chemie Co., Ltd. and Carbodilite LA-1 (30 parts by mass) manufactured by Nisshinbo Chemical Co., Ltd. was used. The details of the components in the mixture are as follows. Stabaxol I...bis-2,6-diisopropylphenylcarbodiimide (molecular weight (=weight average molecular weight): 363) Carbodilite LA-1...poly(4,4'-dicyclohexylmethane carbon dioxide Imine) (weight average molecular weight: about 2000)

The physical properties of the polylactic acid used in Production Example 1 were measured by the following methods. The results are shown in Table 1.

<Optical Purity> The optical purity of the polylactic acid contained in the piezoelectric polymer film produced in Production Example 1 was measured in the following manner. First, a 1.0 g sample (the polymer piezoelectric membrane) was weighed into a 50 mL Erlenmeyer flask, and Isopropyl Alcohol (IPA) 2.5 mL and 5.0 mol/L sodium hydroxide solution were added thereto. mL, and make a sample solution. Then, the Erlenmeyer flask to which the sample solution was added was placed in a water bath at a temperature of 40 ° C, and stirred for about 5 hours until the polylactic acid was completely hydrolyzed. After the stirred sample solution of about 5 hours was cooled to room temperature, 20 mL of a 1.0 mol/L hydrochloric acid solution was added for neutralization, and then the Erlenmeyer flask was sealed and thoroughly stirred and mixed. Then, 1.0 mL of the stirred mixed sample solution was dispensed into a 25 mL dosing bottle, and a mobile phase of the following composition was added thereto to obtain 25 mL of the HPLC sample solution 1. 5 μL of the obtained HPLC sample solution 1 was injected into an HPLC apparatus, and HPLC measurement was performed under the following HPLC measurement conditions. From the measurement results obtained, the area of the peak of the D body derived from polylactic acid and the area of the peak of the L body derived from polylactic acid were determined, and the amount of the L body and the amount of the D body were calculated. Based on the obtained results, the optical purity (% ee) was determined. As a result, the optical purity was 97.0% ee. In addition, in the following Table 1, "LA" means polylactic acid. - HPLC measurement conditions - - Column optical separation column, SUMICHIRAL OA5000 manufactured by Sumitomo Chemical Co., Ltd. (HPLC) Liquid chromatograph manufactured by Japan Seiko Co., Ltd. °C · Composition of mobile phase 1.0 mM - copper (II) sulfate buffer / IPA = 98 / 2 (V / V) (in this mobile phase, the ratio of copper (II) sulfate, IPA, and water is copper sulfate ( II) / IPA / water = 156.4 mg / 20 mL / 980 mL) · Mobile phase flow 1.0 mL / min · Detector UV detector (UV254 nm)

<Weight Average Molecular Weight and Molecular Weight Distribution> The weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) of the polylactic acid were measured by a gel permeation chromatography (GPC) by the following GPC measurement method. -GPC measurement method - - Measurement apparatus GPC-100 manufactured by Waters Corporation - Shodex LF-804 by Pipeline Showa Denko Co., Ltd. - Preparation of sample The polymer pressure produced in Production Example 1 was produced at 40 °C. The electro-membrane was dissolved in a solvent [chloroform], and a sample solution having a concentration of 1 mg/mL was prepared. - Measurement conditions 0.1 mL of the sample solution was introduced into the column at a flow rate of a solvent (chloroform), a temperature of 40 ° C, and a flow rate of 1 mL/min, and the concentration of the sample in the sample solution separated by the column was measured by a differential refractometer. The molecular weight of polylactic acid is a general calibration curve prepared using a polystyrene standard sample, and the weight average molecular weight (Mw) of polylactic acid is calculated.

The properties of the piezoelectric polymer film produced in Production Example 1 were measured by the following methods. The results are shown in Table 1.

<Crystallinity> 10 mg of the piezoelectric polymer film produced in Production Example 1 was accurately weighed, and a differential scanning calorimeter (DSC-1 manufactured by PerkinElmer Co., Ltd.) was used at a temperature elevation rate of 10 The measurement was carried out under the conditions of ° C/min to obtain a melting endothermic curve. Crystallinity was obtained from the obtained melting endothermic curve.

<Standardized Molecular Alignment MORc> For the polymer piezoelectric film produced in Production Example 1, the standardized molecular alignment MORc was measured by a microwave molecular alignment meter MOA-6000 manufactured by Oji Scientific Instruments Co., Ltd. The reference thickness tc is set to 50 μm.

<Internal Haze> The internal haze (hereinafter also referred to as internal haze (H1)) of the piezoelectric polymer film produced in Production Example 1 was obtained by the following method. First, it is prepared to sandwich only a laminate of eucalyptus oil (Shin-Etsu Silicone (trademark), model: KF96-100CS manufactured by Shin-Etsu Chemical Co., Ltd.) between two glass plates, and measure the The haze of the laminate in the thickness direction (hereinafter, the haze (H2)). Then, a laminate of the polymer piezoelectric film having a surface uniformly coated with eucalyptus oil is sandwiched between the two glass sheets, and the haze of the laminate in the thickness direction is measured (hereinafter, it is set as a mist) Degree (H3)). Then, the difference between the two was obtained as shown in the following formula, whereby the internal haze (H1) of the piezoelectric polymer film was obtained. Internal haze (H1) = haze (H3) - haze (H2)

Here, the measurement of haze (H2) and haze (H3) was performed using the following apparatus under the following measurement conditions. Measuring device: manufactured by Tokyo Denshoku Co., Ltd., haze meter TC-HIII DPK Sample size: width 30 mm × length 30 mm Measurement conditions: Temperature according to JIS-K7105: room temperature (25 ° C)

<Piezoelectric constant d ₁₄ (stress-charge method)> The piezoelectric constant of the piezoelectric polymer film is measured based on the "an example of the measurement method of the piezoelectric constant d ₁₄ by the stress-charge method" (in detail, Piezoelectric constant d ₁₄ (stress-charge method)).

[Table 1]

<Production Example 2: Preparation of a coating liquid> 10 kg of an acrylic adhesive SK-Dyne 1811L (manufactured by Soken Chemical Co., Ltd.), a hardener TD-75 (manufactured by Soken Chemical Co., Ltd.) 20 g, and toluene 1 The kg was mixed to obtain a subsequent coating liquid.

<Production Example 3: Preparation of a polymer piezoelectric film having a hard coat layer> An acrylic resin coating liquid (manufactured by Toyo Ink Co., Ltd., anti-adhesive hard coating force Ulduras) by a roll-to-roller TYAB-014) was applied to one main surface of the piezoelectric polymer film produced in Production Example 1. The polymer piezoelectric film coated with the coating liquid was dried in a heating furnace at 80 ° C, and then irradiated with ultraviolet rays having an integrated light amount of 500 mJ/cm ² to form a hard coat layer having a thickness of 2 μm. Further, a hard coat layer having a thickness of 2 μm was formed on the other main surface of the polymer piezoelectric film in the same manner, and a polymer piezoelectric film having a hard coat layer formed on both surfaces was obtained.

[Example 1] The coating liquid obtained in Production Example 2 was applied to a release film by a reverse gravure coating method at a line speed of 2.5 m/min (Mitsui Chemicals Tohcello) The release surface of SP-PET O3-BU manufactured by the company. An adhesive layer was formed on the release film coated with the subsequent coating liquid through a drying oven at a temperature of 100 °C. Furthermore, the release surface of the release film (SP-PET O3-BU manufactured by Mitsui Chemicals, Inc.) was laminated on the adhesive layer and wound up to form a roll-like laminated body A. Mold/layer/release film). Further, the roll-shaped layered product A was stored at room temperature for one week to complete the hardening. The thickness of the layer is then 25 μm. The release film of one side of the roll-shaped layered product A obtained as described above was peeled off by R to R (roll-to-roll), and the polymer piezoelectric film produced in Production Example 1 was laminated on the subsequent layer. The layer was wound up on one side to obtain a roll-shaped laminated body B (release film/adhesion layer/polymer piezoelectric film). Further, the release film on the side of the other roll-shaped layered product A (release film/adhesion layer/release film) is peeled off by R to R, and the polymer piezoelectric film surface layer of the laminate B is laminated. The film was wound up on the exposed adhesive layer to obtain a roll-shaped laminate (film roll layer: release film / adhesive layer / polymer piezoelectric film / adhesive layer / release film).

[Example 2] The adhesive coating liquid obtained in Production Example 2 was applied onto the piezoelectric polymer film produced in Production Example 1 by a reverse gravure coating method at a linear velocity of 2.5 m/min. An adhesive layer was formed on the polymer piezoelectric film coated with the subsequent coating liquid through a drying furnace having a temperature of 70 °C. Furthermore, the release surface of the release film (SP-PET O3-BU manufactured by Mitsui Chemicals, Inc., Co., Ltd.) was laminated on the adhesive layer to obtain a roll-shaped laminated body C (released). Film/adhesion layer/polymer piezoelectric film). Further, a release film was formed on the surface of the piezoelectric polymer film of the roll-shaped layered product C in the same manner as described above, and a release film (SP-PET O3- manufactured by Mitsui Chemicals, Inc.) was laminated. The release surface of BU) was taken up to obtain a roll-shaped laminate (film laminate body: release film / adhesive layer / polymer piezoelectric film / adhesive layer / release film). Further, the roll-shaped laminated body was stored at room temperature for one week to complete the hardening. The thickness of the layer is then 25 μm.

[Example 3] A roll was obtained in the same manner as in Example 1 except that the piezoelectric polymer film produced in Production Example 1 was changed to the polymer piezoelectric film having a hard coat layer produced in Production Example 3. A laminated body (film roll layer: release film / adhesive layer / polymer piezoelectric film / adhesive layer / release film having a hard coat layer).

[Example 4] A roll was obtained in the same manner as in Example 2 except that the piezoelectric polymer film produced in Production Example 1 was changed to the polymer piezoelectric film having a hard coat layer produced in Production Example 3. A laminated body (film roll layer: release film / adhesive layer / polymer piezoelectric film / adhesive layer / release film having a hard coat layer). Further, the roll-shaped laminated body was stored at room temperature for one week to complete the hardening.

[Comparative Example 1] A roll-like laminate (film roll layer: release film/adhesion layer/polymer pressure) was obtained in the same manner as in Example 2 except that the temperature of the drying furnace was changed from 70 °C to 100 °C. Electric film / adhesive layer / release film). Further, the roll-shaped laminated body was stored at room temperature for one week to complete the hardening. The thickness of the layer is then 25 μm.

[Comparative Example 2] The coating liquid obtained in Production Example 2 was manually applied onto the piezoelectric polymer film produced in Production Example 1 by an applicator, and dried in an oven at a temperature of 100 ° C. The formation of the next layer. Further, the release surface of the release film (SP-PET O3-BU manufactured by Mitsui Chemicals, Inc.) was attached to the adhesive layer by a roll to obtain a single-layer laminated body (release film/following) Layer/polymer piezoelectric film). Further, in the same manner as described above, an adhesive layer is formed on the surface of the polymer piezoelectric film of the monolithic laminate, and the release film is bonded by a roll (SP manufactured by Mitsui Chemicals, Inc.) A release sheet of -PET O3-BU) to obtain a monolithic laminate (release film/adhesion layer/polymer piezoelectric film/adhesion layer/release film). Further, the monolithic laminate was stored at room temperature for one week to complete the hardening. The thickness of the layer is then 25 μm.

[Comparative Example 3] A roll was obtained in the same manner as in Comparative Example 1, except that the piezoelectric polymer film produced in Production Example 1 was changed to the polymer piezoelectric film having a hard coat layer produced in Production Example 3. A laminated body (film roll layer: release film / adhesive layer / polymer piezoelectric film / adhesive layer / release film having a hard coat layer).

With respect to the roll-shaped laminate obtained in Examples 1 to 4, Comparative Example 1, and Comparative Example 3, and the monolithic laminate obtained in Comparative Example 2, the acid value and MD of the subsequent layer were evaluated as follows. Dimensional change rate, MD crack and heat and humidity resistance. The evaluation results are shown in Table 2. Furthermore, "-" in Table 2 indicates that there is no measurement data.

<Acid Value of Adhesive Layer> The release film was peeled off from the laminate, and 0.5 g of the exposed adhesive layer was dissolved in a solvent (chloroform), and phenolphthalein was used as an indicator by a 0.005 M KOH (potassium hydroxide) ethanol solution. The titration is carried out to determine the acid value.

<MD size change rate> The polymer piezoelectric film obtained by removing the release film and the adhesive layer from the laminate is cut in the extending direction (MD direction) by 50 mm and in the direction orthogonal to the extending direction (TD direction). ) Cut 50 mm on top and cut out a 50 mm × 50 mm rectangular film. The rectangular film was suspended in an oven set at 100 ° C and annealed for 30 minutes. Then, the size of the rectangular side length of the film in the MD direction before and after the annealing treatment was measured by a high-precision digital length measuring machine (manufactured by Mitutoyo Co., Ltd., Litematic VL-50AS). Further, the dimensional change ratio (%) was calculated according to the following formula, and the dimensional stability was evaluated. The smaller the dimensional change rate, the higher the dimensional stability. (Formula) dimensional change rate (%) = 100 × | (edge length in the MD direction before annealing) - (edge length in the MD direction after annealing) | / (edge length in the MD direction before annealing)

<MD crack> The release film on both sides of the laminate was peeled off, and a polyethylene terephthalate (PET) manufactured by Toray was used using a 2 kg roller (trademark: Lumirror T60) -50) attached to the exposed adhesive layer. Thereby, a laminated structure in which five layers are laminated is produced. That is, the laminated structure includes five layers of a PET/adhesion layer/polymer piezoelectric film/adhesion layer/PET. The laminated structure was punched out into a square of 50 mm × 50 mm using a Pinnacle blade. Further, the obtained laminated structure (50 mm × 50 mm) was heated at 85 ° C for 500 hours. Thereafter, it was allowed to stand at room temperature for 24 hours, and the presence or absence of cracks in the MD direction was visually observed, and the evaluation was performed by the following criteria. A: There is no crack in the polymer piezoelectric film of the laminated structure. B: Cracks are generated in the piezoelectric polymer film of the laminated structure.

<Heat and Heat Resistance> The weight average molecular weight (initial Mw) of the piezoelectric polymer film within 24 hours after the production of the laminate was measured. Then, a rectangular test piece having a length of 50 mm × a width of 50 mm was prepared from the laminate within 24 hours after the production, and the test piece was hung in a thermo-hygrostat maintained at 85 ° C and 85% RH, and Hold for 120 hours. The weight average molecular weight (Mw after the wet heat resistance test) of the polymer piezoelectric film was measured for the test piece, and the Mw maintenance ratio represented by the following formula was evaluated by the following criteria. Formula: Mw maintenance rate = Mw / initial Mw after moisture heat resistance test [Evaluation criteria] A: Mw maintenance rate ≧ 0.6 B: 0.6 > Mw maintenance rate ≧ 0.35 C: Mw maintenance rate < 0.35

[Table 2]

In the first to fourth embodiments, a film-rolled layer body having a MD dimensional change ratio of 1.0% or less was produced. In the film roll layer, no crack was generated in the polymer piezoelectric film during heating, and the polymer piezoelectric film was excellent in moist heat resistance (particularly, Example 1). On the other hand, in Comparative Example 1 and Comparative Example 3, a film wound layer body having a MD dimensional change ratio of 1.0% or more was produced in the piezoelectric polymer film, but in the film roll layer, heating was performed at a high level. Cracks are generated in the molecular piezoelectric film. Further, in Comparative Example 2, a single-layer laminated body was produced, but the heat-resistant property of the polymer piezoelectric film was not sufficient.

The entire disclosure of Japanese Patent Application No. 2015-040385, filed on March 2, 2015, is hereby incorporated by reference. All documents, patent applications, and technical specifications described in the present specification are incorporated herein by reference to the same extent as the following, which are specifically and individually described by reference. And break into the literature, patent applications, and technical specifications.

1, 15‧‧‧ Roll release film
2, 16‧‧‧ release film
3, 13‧‧‧ adhesive
4, 14‧‧‧Next layer
5, 11‧‧‧ Roller polymer piezoelectric film
6,12‧‧‧Polymer piezoelectric film
7, 17‧ ‧ film reel
8, 18‧‧‧ coating device
9, 19 ‧ ‧ drying institutions
10, 20‧ ‧ film roll layer manufacturing device

Fig. 1 is a schematic view showing a method of producing a film roll layer by forming an adhesive layer on a release film in the first embodiment of the present invention. 2 is a schematic view showing a method of producing a film roll layer by forming an adhesive layer on a polymer piezoelectric film in a second embodiment of the present invention.

no

Claims (19)

A film roll layer obtained by winding a laminated film into a roll shape, the laminated film comprising: a polymer piezoelectric film comprising an optically active helical chirality having a weight average molecular weight of 50,000 to 1,000,000 The molecular (A), the crystallinity obtained by the differential scanning calorimetry method is 20% to 80%, and the reference molecular thickness measured by the microwave transmission type molecular alignment meter is set to 50 μm. The product of crystallinity is 40 to 700; and the functional layer (X) is disposed on at least one main surface of the piezoelectric polymer film; and the functional layer is removed from the laminated film at 100 ° C The dimensional change rate of the piezoelectric polymer film obtained in (X) when heated for 30 minutes is 1.0% or less in the longitudinal direction. The film-rolled layer body according to claim 1, wherein the functional layer (X) has an acid value of 10 mgKOH/g or less. The film reel body according to claim 1 or 2, wherein the functional layer (X) is an adhesive layer. The film-rolled body according to the first or second aspect of the invention, wherein the functional layer (X) has an acid value of 0.01 mgKOH/g or more. The film-rolled layer body according to the first or second aspect of the invention, wherein the total amount of nitrogen in the functional layer (X) is from 0.05% by mass to 10% by mass. The film roll layer body according to the above aspect, wherein the functional layer (X) is in contact with the polymer piezoelectric film. The film roll layer body according to the above-mentioned item, wherein the laminated film has a refractive index adjusting layer between the polymer piezoelectric film and the functional layer (X), and is easy to follow. At least one of a layer, a hard coat layer, an antistatic layer, and an anti-blocking layer. The film-rolled layer body according to the first or second aspect of the invention, wherein the polymer piezoelectric film comprises, with respect to 100 parts by mass of the helical chiral polymer (A), having a carbon dioxide selected from the group consisting of carbon dioxide One or more functional groups in the group consisting of an imine group, an epoxy group, and an isocyanate group, and the stabilizer (B) having a weight average molecular weight of 200 to 60,000 is 0.01 parts by mass to 10 parts by mass. The film reel body according to claim 8, wherein the stabilizer (B) comprises one or more selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group. a stabilizer (B1) having a functional group and a weight average molecular weight of 200 to 900, and having two or more groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group in one molecule A stabilizer (B2) having one or more functional groups and having a weight average molecular weight of 1,000 to 60,000. The film-rolled layer body according to claim 1 or 2, wherein the polymer piezoelectric film has an internal haze of 50% or less with respect to visible light, and is stressed at 25 ° C - The piezoelectric constant d ₁₄ measured by the charge method is 1 pC/N or more. The film reel body according to the first or second aspect of the invention, wherein the polymer piezoelectric film has an internal haze of 13% or less with respect to visible light, and is high with respect to the spiral chirality. 100 parts by mass of the molecule (A), comprising a stabilizer having one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group, and having a weight average molecular weight of 200 to 60,000 ( B) 0.01 parts by mass to 2.8 parts by mass. The film-rolled layer body according to claim 1 or 2, wherein the helical chiral polymer (A) is a polymer having a main chain comprising a repeating unit represented by the following formula (1) Lactic acid polymer, . The film-rolled layer body according to the first or second aspect of the invention, wherein the optical purity of the helical chiral polymer (A) is 95.00% or more. The film-rolled layer body according to the first or second aspect of the invention, wherein the content of the helical chiral polymer (A) in the polymer piezoelectric film is 80% by mass or more. The film reel body according to claim 1 or 2, wherein the laminated film further comprises a side disposed from the functional layer (X) and disposed on the side of the polymer piezoelectric film The release film on the opposite side. The film reel body according to claim 15, wherein the length of the laminated film in the longitudinal direction is 10 m or more. A method for producing a film roll layer, which is a method for producing a film roll layer body according to claim 15, which comprises: imparting a functional layer forming agent for forming the functional layer (X) to a step of forming the functional layer (X) on the main surface of the release film; the function is viewed from a side opposite to the side on which the release film is disposed as viewed from the functional layer (X) a step of bonding the layer (X) to the polymer piezoelectric film to form the laminated film, and a step of winding the formed laminated film into a roll shape. A method for producing a film roll layer, which is a method for producing a film roll layer body according to claim 15, comprising: coating a functional layer forming agent for forming the functional layer (X) a step of forming the functional layer (X) by drying the applied functional layer forming agent on at least one main surface of the piezoelectric polymer film at a temperature of 90 ° C or lower; (X) a step of forming the laminated film by bonding the functional layer (X) to the release film on the side opposite to the side on which the piezoelectric polymer film is disposed, and the side opposite to the side on which the piezoelectric polymer film is disposed; The formed laminated film is wound into a roll shape. The method for producing a film reel body according to claim 17 or claim 18, wherein the functional layer (X) is an adhesive layer, and the functional layer forming agent is an adhesive.