JP6408124B2 - Film wound layer and manufacturing method thereof - Google Patents

Description

  The present invention relates to a film wound body having a polymer piezoelectric film and a method for producing the same.

In recent years, polymer piezoelectric materials using optically active aliphatic polyesters (for example, polylactic acid polymers) have been reported.
For example, a polymer piezoelectric material that exhibits a piezoelectric constant of about 10 pC / N at room temperature by stretching a molded product of polylactic acid has been disclosed (for example, see Patent Document 1).
In addition, in order to make polylactic acid crystals highly oriented, it has also been reported that high piezoelectricity of about 18 pC / N is obtained by a special orientation method called a forging method (see, for example, Patent Document 2).
Patent Document 1: JP-A-5-152638 Patent Document 2: JP-A-2005-213376

By the way, on the polymer piezoelectric material, at least a part of the polymer piezoelectric material is used for the purpose of protecting the polymer piezoelectric material or bonding the polymer piezoelectric material to another member (polymer film, glass, electrode, etc.). In some cases, a layer in contact with the piezoelectric body is provided. An adhesive layer may be used as such a layer.
Further, when a sensor or an actuator is actually manufactured as a device using a polymer piezoelectric material, it is industrially preferable to adopt a roll-to-roll continuous process from the viewpoint of productivity. For this purpose, it is necessary to supply a wound body (roll body) in which a polymer piezoelectric body is wound in a long length. At this time, if the roll body of the polymer piezoelectric body has an adhesive layer, it is not necessary to form the adhesive layer in a subsequent process, and the process can be simplified. Furthermore, since a continuous process by roll-to-roll can be employed in a state where the adhesive layer is formed, the total productivity until the device is manufactured is improved.
Here, in the roll-to-roll continuous process, it is necessary to prevent bending of the polymer piezoelectric material between the rolls, and tension is generated in the polymer piezoelectric material in the process flow direction (MD direction). To do. Furthermore, polymer piezoelectric materials containing aliphatic polyesters (helical chiral polymers) such as polylactic acid have low heat resistance, and when heat is applied in the process of forming an adhesive layer on the polymer piezoelectric material, the polymer piezoelectric material is subjected to tension. The body may be stretched and the dimensional change rate of the polymer piezoelectric material may be deteriorated, or the aliphatic polyester such as polylactic acid may be decomposed by heat to deteriorate the heat and moisture resistance of the polymer piezoelectric material. .
Further, in order to develop piezoelectricity in the polymer piezoelectric material, it is preferable to align the molecular chain in one direction, but there is a problem that it is easy to tear in the alignment direction.
For this reason, when trying to use as a device a polymer piezoelectric body in which the dimensional change rate is deteriorated and the molecular chain is mainly oriented in one direction, the polymer due to the shrinkage difference between the polymer piezoelectric body and the other member laminated. There is a risk of cracks in the piezoelectric body.

  As a result of diligent study, the present inventor has found that in a film wound layer obtained by winding a laminated film having a polymer piezoelectric material containing polyester (helical chiral polymer) and a functional layer such as an adhesive layer in a roll shape, By reducing the dimensional change rate of a piezoelectric polymer containing a chiral polymer, it is possible to suppress the occurrence of cracks in the polymer piezoelectric film when heated, and to improve the moisture and heat resistance of the polymer piezoelectric film. I found it.

  The present invention has been made in view of the above, and provides a film wound layer body that suppresses the occurrence of cracks in a polymer piezoelectric film when heated and is excellent in moisture and heat resistance of the polymer piezoelectric film, and a method for producing the same. The purpose is to do.

Specific means for achieving the above object are as follows, for example.
<1> A helical chiral polymer (A) having an optical activity having a weight average molecular weight of 50,000 to 1,000,000, crystallinity obtained by DSC method of 20% to 80%, and microwave transmission A polymer piezoelectric film in which the product of the normalized molecular orientation MORc and the crystallinity is 40 to 700 when the standard thickness measured by a type molecular orientation meter is 50 μm, and at least one of the polymer piezoelectric films The polymer piezoelectric film obtained by removing the functional layer (X) from the laminated film, the laminated film having a functional layer (X) provided on the main surface of the laminated film wound in a roll shape The film winding layered body whose dimensional change rate when heated at 100 ° C. for 30 minutes is 1.0% or less in the MD direction.
<2> The film wound layer according to <1>, wherein the acid value of the functional layer (X) is 10 mgKOH / g or less.
<3> The film layered product according to <1> or <2>, wherein the functional layer (X) is an adhesive layer.
<4> The wound film layer according to any one of <1> to <3>, wherein the acid value of the functional layer (X) is 0.01 mgKOH / g or more.
<5> The film winding 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.
<6> The film wound layer according to any one of <1> to <5>, wherein the functional layer (X) is in contact with the polymer piezoelectric film.
<7> The laminated film includes at least one of a refractive index adjusting layer, an easy adhesion layer, a hard coat layer, an antistatic layer, and an antiblock layer between the polymer piezoelectric film and the functional layer (X). The film winding layered body according to any one of <1> to <6>, having a layer.
<8> The polymer piezoelectric film includes a stabilizer (B) having a weight average molecular weight of 200 to 60000 having one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group. <1>-<7> The film winding layered body as described in any one of 0.01 mass part-10 mass parts is included with respect to 100 mass parts of helical chiral polymers (A).
<9> The stabilizer (B) is a stabilizer (B1) having a weight average molecular weight of 200 to 900 having one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group. And a stabilizer (B2) having a weight average molecular weight of 1,000 to 60000 having two or more functional groups selected from the group consisting of carbodiimide group, epoxy group and isocyanate group in one molecule <8 > Film-wrapped layered body according to
<10> The piezoelectric polymer film is 50% or less internal haze to visible light, and the stress at 25 ° C. - piezoelectric constant _{d 14} measured by the charge method is 1 pC / N or more <1> to <9> The film winding layered body according to any one of 9>.
<11> The polymer piezoelectric film has an internal haze with respect to visible light of 13% or less and a weight average molecular weight having at least one functional group selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group. <1> to <10> containing 0.01 to 2.8 parts by mass of the stabilizer (B) having a molecular weight of 200 to 60000 with respect to 100 parts by mass of the helical chiral polymer (A). The film-wrapped layer described in 1.
<12> The helical chiral polymer (A) is any one of <1> to <11>, which is a polylactic acid polymer having a main chain including a repeating unit represented by the following formula (1). The film winding layered body of description.

<13> The film wound layer according to any one of <1> to <12>, wherein the helical chiral polymer (A) has an optical purity of 95.00% ee or more.
<14> The film wound layer according to any one of <1> to <13>, wherein the content of the helical chiral polymer (A) in the polymer piezoelectric film is 80% by mass or more.
<15> The laminated film further includes a release film disposed on the side opposite to the side on which the polymer piezoelectric film is disposed when viewed from the functional layer (X). <1> to <14> The film winding layered body according to any one of 14>.
<16> The laminated film according to <15>, wherein the laminated film has a length in the MD direction of 10 m or more.

<17> The method for producing a film-layered body according to <15> or <16>, wherein a functional layer forming agent for forming the functional layer (X) is provided on the main surface of the release film. The functional layer (X) and the polymer piezoelectric film are formed on the opposite side of the step of forming the functional layer (X) and the side on which the release film is disposed as viewed from the functional layer (X). The manufacturing method of the film winding layer body which includes the process of bonding a film together and forming the said laminated | multilayer film, and the process of winding the formed said laminated | multilayer film in roll shape.
<18> A method for producing a wound film body according to <15> or <16>, wherein the functional layer is formed to form the functional layer (X) on at least one main surface of the polymer piezoelectric film. Coating the functional layer forming agent and drying the coated functional layer forming agent at a temperature of 90 ° C. or less to form the functional layer (X), and the polymer piezoelectric film as viewed from the functional layer (X). A step of bonding the functional layer (X) and the release film to form the laminated film on the side opposite to the side on which the laminated film is formed, a step of winding the formed laminated film into a roll, and The manufacturing method of the film winding layer body containing this.
<19> The method according to <17> or <18>, wherein the functional layer (X) is an adhesive layer, and the functional layer forming agent is an adhesive.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the crack to a polymeric piezoelectric film when heated can be suppressed, and the film winding layer body which is excellent in the heat-and-moisture resistance of a polymeric piezoelectric film, and its manufacturing method can be provided.

In 1st embodiment of this invention, it is the schematic which shows the method of forming an adhesive layer in a release film and manufacturing a film winding layered body. In 2nd embodiment of this invention, it is the schematic which shows the method of forming an adhesive layer in a polymeric piezoelectric film and manufacturing a film winding layered body.

Hereinafter, one embodiment of the film wound layer of the present invention is described.
In this specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
Further, in the present specification, “film” is a concept including not only what is generally called “film” but also what is generally called “sheet”.
Moreover, in this specification, "(meth) acryl group" represents at least one of an acryl group and a methacryl group.

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

<Film wound layer>
The film wound layer according to an embodiment of the present invention includes a helical chiral polymer (A) having an optical activity having a weight average molecular weight of 50,000 to 1,000,000, and has a crystallinity of 20% obtained by a DSC method. Polymer piezoelectric, which is ˜80% and the product of the normalized molecular orientation MORc and the crystallinity when the reference thickness measured by a microwave transmission type molecular orientation meter is 50 μm is 40 to 700 A laminated film having a film and a functional layer (X) provided on at least one main surface of the polymer piezoelectric film is wound in a roll shape, and the functional layer (X) is formed from the laminated film. The dimensional change rate when the polymer piezoelectric film obtained by the removal is heated at 100 ° C. for 30 minutes is 1.0% or less in the MD direction.

  In the film wound layer according to the present embodiment, 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 is wound in a roll shape. The dimensional change rate when the polymer piezoelectric film obtained by removing the functional layer (X) from the laminated film is heated at 100 ° C. for 30 minutes is 1.0% or less in the MD direction. Therefore, for example, when a laminated body is formed using a film wound layer body, the occurrence of cracks in the polymer piezoelectric film when heated is suppressed, and the helical chiral polymer ( The decomposition of A) is suppressed, and the polymer piezoelectric film is excellent in heat and moisture resistance. Furthermore, since the dimensional change rate when the polymer piezoelectric film is heated at 100 ° C. for 30 minutes is 1.0% or less in the MD direction, it has excellent dimensional stability and is incorporated in devices such as speakers and touch panels. When used, the dimensions hardly change, and the occurrence of malfunctions of devices and the like is suppressed.

  Moreover, the film wound body according to the present embodiment has a polymer piezoelectric film, and this polymer piezoelectric film has a helical chiral high molecular weight having an optical activity of a weight average molecular weight (Mw) of 50,000 to 1,000,000. The molecule (A) (hereinafter also referred to as “helical chiral polymer (A)”) is included. 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 when a polymer piezoelectric film is obtained by molding (for example, extrusion molding) is improved.

The polymer piezoelectric film has a crystallinity of 20% to 80% obtained by the DSC method. For this reason, the piezoelectric polymer film has a good balance of piezoelectricity, transparency and longitudinal tear strength (tear strength in a specific direction), and it is difficult to whiten or break when the polymer piezoelectric film is stretched. It's easy to do.
More specifically, when the crystallinity is 20% or more, the piezoelectricity of the polymer piezoelectric film is maintained high, and when the crystallinity is 80% or less, the longitudinal crack strength and It can suppress that transparency falls.

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

[Polymer piezoelectric film]
The film wound body according to the present embodiment includes a helical chiral polymer (A) having optical activity, has a crystallinity of 20% to 80% obtained by the DSC method, and has a microwave transmission molecular orientation. The product of the normalized molecular orientation MORc and the crystallinity when the reference thickness measured by the meter is 50 μm is 40 to 700.
Hereinafter, physical properties of the polymer piezoelectric film, components contained in the polymer piezoelectric film, and the like will be described in detail.

[Helical Chiral Polymer with Optical Activity (A)]
The polymer piezoelectric film used in the present embodiment includes a helical chiral polymer (A) having optical activity. The helical chiral polymer (A) having optical activity refers to a polymer having molecular optical activity in which the molecular structure is a helical structure and having a weight average molecular weight of 50,000 to 1,000,000.
Examples of the helical chiral polymer (A) include polypeptides, cellulose, cellulose derivatives, polylactic acid polymers, polypropylene oxide, poly (β-hydroxybutyric acid), and the like. Examples of the polypeptide include poly (glutarate γ-benzyl), poly (glutarate γ-methyl), and the like. Examples of the cellulose derivative include cellulose acetate and cyanoethyl cellulose.

  From the viewpoint of improving the piezoelectricity of the polymer piezoelectric film, the helical chiral polymer (A) preferably has an optical purity of 95.00% ee or more, more preferably 97.00% ee or more. It is more preferably 99.00% ee or more, and particularly preferably 99.99% ee or more. Desirably, it is 100.00% ee. By setting the optical purity of the helical chiral polymer (A) within the above range, the packing property of the polymer crystal that exhibits piezoelectricity is enhanced, and as a result, the piezoelectricity is considered to be enhanced.

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 body weight−D body weight | / (L body weight + D body weight)
That is, “the amount difference (absolute value) between the amount of L-form [mass%] of helical chiral polymer (A) and the amount of D-form [mass%] of helical chiral polymer (A)” (absolute value) ”is expressed as“ helical chiral “100” is obtained by dividing (dividing by) the total amount of the amount (mass%) of the L isomer of the polymer (A) and the amount of the D isomer (mass%) of the helical chiral polymer (A). The value obtained by multiplying (multiplying) by is defined as optical purity.

  The amount of L-form [mass%] of the helical chiral polymer (A) and the amount of D-form [mass%] of the helical chiral polymer (A) can be obtained by a method using high performance liquid chromatography (HPLC). Use the value. Details of the specific measurement will be described later.

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

  Examples of the compound having the repeating unit represented by the formula (1) as a main chain include polylactic acid polymers. Among them, polylactic acid is preferable, and L-lactic acid homopolymer (PLLA) or D-lactic acid homopolymer (PDLA) is most preferable.

  The polylactic acid polymer refers to “polylactic acid”, “copolymer of L-lactic acid or D-lactic acid and a copolymerizable polyfunctional compound”, or a mixture of both. The above-mentioned “polylactic acid” is a polymer in which lactic acid is polymerized by an ester bond and is connected for a long time, a lactide method via lactide, a direct polymerization method in which lactic acid is heated in a solvent under reduced pressure and polymerized while removing water. It is known that can be manufactured by. Examples of the “polylactic acid” include a homopolymer of L-lactic acid, a homopolymer of D-lactic acid, a block copolymer containing at least one polymer of L-lactic acid and D-lactic acid, and at least one of L-lactic acid and D-lactic acid. The graft copolymer containing the polymer of these is mentioned.

  Examples of the “copolymerizable polyfunctional compound” include glycolic acid, dimethyl glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxypropanoic acid, 3-hydroxypropanoic acid, 2-hydroxyvaleric acid, 3 -Hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 2-hydroxycaproic acid, 3-hydroxycaproic acid, 4-hydroxycaproic acid, 5-hydroxycaproic acid, 6-hydroxycaproic acid, 6-hydroxy Hydroxycarboxylic acids such as methyl caproic acid and mandelic acid, glycolides, cyclic esters such as β-methyl-δ-valerolactone, γ-valerolactone, and ε-caprolactone, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid , Pimelic acid, azelaic acid, sebacic acid, undecanedioic acid, Polycarboxylic acids such as candioic acid and terephthalic acid, anhydrides thereof, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1, 4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, tetramethylene Examples include glycols, polyhydric alcohols such as 1,4-hexanedimethanol, polysaccharides such as cellulose, and aminocarboxylic acids such as α-amino acids.

  Examples of the “copolymerizable polyfunctional compound” include the compounds described in paragraph 0028 of International Publication No. 2013/054918 pamphlet.

  Examples of the “copolymer of L-lactic acid or D-lactic acid and a copolymerizable polyfunctional compound” include a block copolymer or a graft copolymer having a polylactic acid sequence capable of forming a helical crystal.

  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 polymer, a structure derived from lactic acid in the polylactic acid polymer and a structure derived from a compound copolymerizable with lactic acid (copolymer component) The copolymer component is preferably 20 mol% or less based on the total number of moles.

The helical chiral polymer (A) (for example, polylactic acid polymer) is obtained by, for example, directly dehydrating and condensing lactic acid described in JP-A-59-096123 and JP-A-7-033861. Alternatively, it can be produced by a ring-opening polymerization method using lactide which is a cyclic dimer of lactic acid described in US Pat. Nos. 2,668,182 and 4,057,357.
Furthermore, the helical chiral polymer (A) (for example, polylactic acid polymer) obtained by each of the production methods described above is prepared by, for example, converting polylactic acid by the lactide method so that the optical purity is 95.00% ee or more. When manufacturing, it is preferable to polymerize lactide whose optical purity is improved to 95.00% ee or higher by crystallization operation.

≪Weight average molecular weight of helical chiral polymer (A) ≫
The helical chiral polymer (A) used in the present embodiment has a weight average molecular weight (Mw) of 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 when formed into a 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 when a polymer piezoelectric film is obtained by molding (for example, extrusion molding) is improved. 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 when obtaining a polymer piezoelectric film.

  Further, the molecular weight distribution (Mw / Mn) of the helical chiral polymer (A) is preferably 1.1 to 5 and more preferably 1.2 to 4 from the viewpoint of the strength of the polymer piezoelectric film. preferable. Furthermore, it is preferable that it is 1.4-3. In addition, the weight average molecular weight Mw and the molecular weight distribution (Mw / Mn) of the helical chiral polymer (A) (for example, polylactic acid polymer) are measured by the following GPC measurement method using gel permeation chromatography (GPC). Measured.

-GPC measuring device-
Waters GPC-100
-Column-
Showex Denko KK, Shodex LF-804
-Sample preparation-
The helical chiral polymer (A) is dissolved in a solvent (for example, chloroform) at 40 ° C. to prepare a sample solution having a concentration of 1 mg / mL.
-Measurement conditions-
0.1 mL of the sample solution is introduced into the column at a solvent [chloroform], a temperature of 40 ° C., and a flow rate of 1 mL / min.

  The sample concentration in the sample solution separated by the column is measured with a differential refractometer. A universal calibration curve is created with a polystyrene standard sample, and the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the helical chiral polymer (A) are calculated.

Commercially available polylactic acid may be used as the polylactic acid polymer that is an example of the helical chiral polymer (A). Commercially available polylactic acid, for example, PURAC Co. PURASORB (PD, PL), manufactured by Mitsui Chemicals, Inc. LACEA (H-100, H- 400), NatureWorks LLC Corp. ^Ingeo TM Biopolymer, include equal .

  When a polylactic acid polymer is used as the helical chiral polymer (A), in order to increase the weight average molecular weight (Mw) of the polylactic acid polymer to 50,000 or more, the helical chiral polymer can be obtained by the lactide method or the direct polymerization method. It is preferable to produce the molecule (A).

The piezoelectric polymer film used in the present embodiment may contain only one kind of the above-described helical chiral polymer (A), or may contain two or more kinds.
In the polymer piezoelectric film used in the present embodiment, the content of the helical chiral polymer (A) (the total content when there are two or more types; the same shall apply hereinafter) is not particularly limited, but the polymer piezoelectric film It is preferable that it is 80 mass% or more with respect to the total mass.
When the content is 80% by mass or more, the piezoelectric constant tends to be larger.

≪MD dimensional change rate≫
In the film wound layer according to this embodiment, the dimensional change rate (MD dimension) in the MD direction when the polymer piezoelectric film obtained by removing the functional layer (X) from the laminated film is heated at 100 ° C. for 30 minutes. Change rate) is 1.0% or less. A smaller dimensional change rate indicates higher 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 to 50 mm in the stretching direction (MD direction) and 50 mm in a direction (TD direction) perpendicular to the stretching direction, and a 50 mm × 50 mm rectangular film is cut out. In addition, when a laminated | multilayer film has a mold release film, another layer, etc., a mold release film, another layer, etc. are removed with functional layer (X). This rectangular film is suspended in an oven set at 100 ° C. and annealed for 30 minutes. Thereafter, the dimension of the film rectangular side length in the MD direction before and after the annealing treatment is measured with a high-precision digital length measuring device (manufactured by Mitutoyo Corporation, Lightmatic VL-50AS). And according to the following formula, a dimensional change rate (%) is calculated, and dimensional stability is evaluated.
(Expression) Dimensional change rate (%) = 100 × | (side length in MD direction before annealing) − (side length in MD direction after annealing) | / (side length in MD direction before annealing)

  The dimensional change rate in the MD direction is preferably 0.9% or less and more preferably 0.8% or less from the viewpoint of further improving the dimensional stability.

≪Crystallinity≫
The crystallinity of the polymer piezoelectric film is determined by the DSC method. The crystallinity of the polymer piezoelectric film is 20% to 80%, preferably 30% to 70%, and more preferably 35% to 60%. If the crystallinity is within the above range, the piezoelectricity, transparency, and longitudinal tear strength of the polymer piezoelectric film are well balanced, and when the polymer piezoelectric film is stretched, whitening and breakage are unlikely to occur and it is easy to manufacture.
When the degree of crystallinity is 20% or more, the piezoelectricity of the polymer piezoelectric film is maintained high.
Moreover, it can suppress that longitudinal crack strength and transparency fall because a crystallinity degree is 80% or less.

  For example, the crystallinity of the polymer piezoelectric film can be adjusted in the range of 20% to 80% by adjusting the crystallization and stretching conditions when producing the polymer piezoelectric film.

≪Standardized molecular orientation MORc≫
The normalized molecular orientation MORc of the polymer piezoelectric film is preferably 2.0 to 15.0. The normalized molecular orientation MORc is a value determined based on the “molecular orientation degree MOR” which is an index indicating the degree of orientation of the helical chiral polymer (A). If the normalized molecular orientation MORc is 2.0 or more, there are many molecular chains (for example, polylactic acid molecular chains) of the helical chiral polymer (A) arranged in the stretching direction, and as a result, the rate of formation of oriented crystals is high. Thus, the polymer piezoelectric film can exhibit higher piezoelectricity. If the normalized molecular orientation MORc is 15.0 or less, the longitudinal tear strength of the polymer piezoelectric film is further improved.

  Here, the molecular orientation degree MOR (Molecular Orientation Ratio) is measured by the following microwave measurement method. That is, the surface of the polymer piezoelectric film in the microwave traveling direction in the microwave resonant waveguide of a known microwave transmission type molecular orientation meter (also referred to as a microwave molecular orientation degree measuring device). Arrange so that (film surface) is vertical. Then, in a state where the sample is continuously irradiated with the microwave whose vibration direction is biased in one direction, the polymer piezoelectric film is rotated 0 to 360 ° in a plane perpendicular to the traveling direction of the microwave, and the sample is transmitted. The degree of molecular orientation MOR is obtained by measuring the measured microwave intensity.

The normalized molecular orientation MORc is a molecular orientation degree 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)
The normalized molecular orientation MORc can be measured with a known molecular orientation meter such as a microwave molecular orientation meter MOA-2012A or MOA-6000 manufactured by Oji Scientific Instruments Co., Ltd., at a resonance frequency in the vicinity of 4 GHz or 12 GHz.

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

  The normalized molecular orientation MORc is, for example, when the polymer piezoelectric film is a stretched film, heat treatment conditions (heating temperature and heating time) before stretching, stretching conditions (stretching ratio, stretching temperature and stretching speed), etc. Can be controlled by.

The normalized molecular orientation MORc can be converted into a birefringence Δn obtained by dividing the retardation amount (retardation) by the thickness of the film. Specifically, retardation can be measured using RETS100 manufactured by Otsuka Electronics Co., Ltd. MORc and Δn are approximately in a linear proportional relationship, and when Δn is 0, MORc is 1.
For example, when the helical chiral polymer (A) is a polylactic acid polymer and the birefringence Δn of the polymer piezoelectric film is measured at a measurement wavelength of 550 nm, the normalized molecular orientation MORc is 2.0. The birefringence Δn 0.005 can be converted, and if the normalized molecular orientation MORc is 4.0, the birefringence Δn 0.01 can be converted.

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

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

  In addition, the normalized molecular orientation MORc is controlled by the crystallization conditions (for example, heating temperature and heating time) and the stretching conditions (for example, stretching ratio, stretching temperature, and stretching speed) when the polymer piezoelectric film is manufactured. sell.

«Piezoelectric constant _{d 14} (stress - charge method)»
Piezoelectricity of polymeric piezoelectric film, for example, can be assessed by measuring the piezoelectric constant d ₁₄ of the piezoelectric polymer film.
Hereinafter, the stress - describing an example of a method for measuring a piezoelectric constant d ₁₄ due to charge method.

  First, the polymer piezoelectric film is cut to 150 mm in a direction formed by 45 ° with respect to the stretching direction (MD direction) and 50 mm in a direction orthogonal to the direction formed by 45 ° to produce a rectangular test piece. Next, the test piece obtained on the SIP-600 test stand made by Showa Vacuum Co., Ltd. is set, and one side of the test piece is set so that the deposition thickness of aluminum (hereinafter referred to as Al) is about 50 nm. Al is vapor-deposited on the substrate. Next, vapor deposition is similarly performed on the other side of the test piece, and Al is coated on both sides of the test piece to form an Al conductive layer.

  A test piece of 150 mm x 50 mm with an Al conductive layer formed on both sides is 120 mm in a direction of 45 ° with respect to the stretching direction (MD direction) of the polymer piezoelectric film, and 10 mm in a direction perpendicular to the direction of 45 °. Cut and cut out a rectangular film of 120 mm × 10 mm. This is a piezoelectric constant measurement sample.

The obtained sample is set in a tensile tester (manufactured by AND, TENSILON RTG-1250) with a distance between chucks of 70 mm so as not to be loosened. A force is periodically applied so that the applied force reciprocates between 4N and 9N at a crosshead speed of 5 mm / min. At this time, in order to measure the amount of charge generated in the sample according to the applied force, a capacitor having a capacitance Qm (F) is connected in parallel to the sample, and the voltage V between the terminals of the capacitor Cm (95 nF) is converted into a buffer amplifier. Measure through. The above measurement is performed under a temperature condition of 25 ° C. The generated charge amount Q (C) is calculated as the product of the capacitor capacitance Cm and the terminal voltage Vm. Piezoelectric constant d ₁₄ is calculated by the following equation.
d ₁₄ = (2 × t) / L × Cm · ΔVm / ΔF
t: Sample thickness (m)
L: Distance between chucks (m)
Cm: Capacitor capacity in parallel (F)
ΔVm / ΔF: Ratio of change in voltage between capacitor terminals to change in force

The higher the piezoelectric constant d ₁₄ is, the larger the displacement of the polymer piezoelectric film with respect to the voltage applied to the polymer piezoelectric film, and conversely, the voltage generated with respect to the force applied to the polymer piezoelectric film increases. It is useful as a film.
Specifically, in the polymeric piezoelectric film in the present embodiment, the stress at 25 ° C. - piezoelectric constant _{d 14} measured by the charge method is preferably at least 1 pC / N, more preferably at least 3pC / N, 5pC / N or more Is more preferable, and 6 pC / N or more is particularly preferable. The upper limit of the piezoelectric constant d ₁₄ is not particularly limited, from the viewpoint of the balance, such as transparency, preferably less 50pc / N is a polymer piezoelectric film using a helical chiral polymer, more preferably at most 30 pC / N.
From the viewpoint of the balance with similarly transparency is preferably a piezoelectric constant d ₁₄ measured by a resonance method is not more than 15pC / N.

≪Transparency (internal haze) ≫
The transparency of the polymer piezoelectric film used in the present embodiment can be evaluated by, for example, visual observation or haze measurement.
The polymer piezoelectric film preferably has an internal haze with respect to visible light (hereinafter also simply referred to as “internal haze”) of 50% or less, more preferably 20% or less, and further preferably 13% or less. Preferably, it is more preferably 5% or less, particularly preferably 2.0% or less, and most preferably 1.0% or less.
The lower the internal haze of the polymer piezoelectric film used in the present embodiment, the better. However, from the viewpoint of balance with the piezoelectric constant, etc., 0.01% to 15% is preferable, and 0.01% to It is more preferably 10%, further preferably 0.1% to 5%, and particularly preferably 0.1% to 1.0%.

In the present embodiment, “internal haze” refers to haze excluding haze due to the shape of the outer surface of the polymer piezoelectric film.
Further, the “internal haze” here is a value when measured at 25 ° C. in accordance with JIS-K7105 with respect to the polymer piezoelectric film.

More specifically, the internal haze (hereinafter also referred to as “internal haze H1”) refers to a value measured as follows.
Specifically, first, a haze in the optical path length direction (hereinafter also referred to as “haze H2”) was measured for a cell having an optical path length of 10 mm filled with silicone oil. Next, the polymer piezoelectric film is immersed in the silicone oil of the cell so that the optical path length direction of the cell and the normal direction of the film are parallel, and the haze in the optical path length direction of the cell in which the polymer piezoelectric film is immersed (Hereinafter also referred to as “haze H3”). Both haze H2 and haze H3 are measured at 25 ° C. in accordance with JIS-K7105.
Based on the measured haze H2 and haze H3, the internal haze H1 is obtained according to the following formula.
Internal haze (H1) = Haze (H3) -Haze (H2)

The haze H2 and the haze H3 can be measured using, for example, a haze measuring machine [manufactured by Tokyo Denshoku Co., Ltd., TC-HIII DPK].
As the silicone oil, for example, “Shin-Etsu Silicone (trademark), model number KF-96-100CS” manufactured by Shin-Etsu Chemical Co., Ltd. can be used.

  The thickness of the polymer piezoelectric 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.

[Stabilizer (B)]
The polymer piezoelectric film used in the present embodiment has a weight average molecular weight of 200 to 60000 having at least one functional group selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group as a stabilizer (B). A compound may be contained. Thereby, the heat-and-moisture resistance of a polymeric piezoelectric film improves more.
Furthermore, the polymer piezoelectric film preferably has one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group in one molecule as the stabilizer (B).
As the stabilizer (B), “stabilizer (B)” described in paragraphs 0039 to 0055 of International Publication No. 2013/054918 can be used.

Examples of the compound containing a carbodiimide group (carbodiimide compound) that can be used as the stabilizer (B) include a monocarbodiimide compound, a polycarbodiimide compound, and a cyclic carbodiimide compound.
As the monocarbodiimide compound, dicyclohexylcarbodiimide, bis-2,6-diisopropylphenylcarbodiimide, and the like are preferable.
Moreover, as a polycarbodiimide compound, what was manufactured by the various method can be used. Conventional methods for producing polycarbodiimides (for example, U.S. Pat. No. 2,941,956, JP-B-47-33279, J.0rg.Chem.28, 2069-2075 (1963), Chemical Review 1981, Vol. 81 No. 1). 4, p619-621) can be used. Specifically, a carbodiimide compound described in Japanese Patent No. 4084953 can also be used.
Examples of the polycarbodiimide compound include poly (4,4′-dicyclohexylmethanecarbodiimide), poly (N, N′-di-2,6-diisopropylphenylcarbodiimide), poly (1,3,5-triisopropylphenylene-2, 4-carbodiimide and the like.
The cyclic carbodiimide compound can be synthesized based on the method described in JP2011-256337A and JP2013-256485A.
Commercially available products may be used as the carbodiimide compound, for example, Tokyo Chemical Industry Co., Ltd., B2756 (trade name), Nisshinbo Chemical Co., Ltd., Carbodilite LA-1, Rhein Chemie, Stabaxol P, Stabaxol P400, Stabaxol. I (both are trade names).

  Examples of the compound (isocyanate compound) containing an isocyanate group in one molecule that can be used as the stabilizer (B) include 3- (triethoxysilyl) propyl isocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate. Diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, Etc.

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

As described above, the weight average molecular weight of the stabilizer (B) is 200 to 60000, more preferably 200 to 30000, and still more preferably 300 to 18000.
When the weight average molecular weight of the stabilizer (B) is within the above range, the stabilizer is more easily moved, and the effect of improving the heat and moisture resistance is more effectively exhibited.
The weight average molecular weight of the stabilizer (B) is particularly preferably 200 to 900. In addition, the weight average molecular weight 200-900 substantially corresponds with the number average molecular weight 200-900. Further, when the weight average molecular weight is 200 to 900, the molecular weight distribution may be 1.0. In this case, “weight average molecular weight 200 to 900” can be simply referred to as “molecular weight 200 to 900”. .

When the polymer piezoelectric film contains the stabilizer (B), the polymer piezoelectric film may contain only one kind of stabilizer (B) or 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) (when there are two or more kinds, the total content; the same shall apply hereinafter). , Preferably from 0.01 parts by weight to 10 parts by weight, more preferably from 0.01 parts by weight to 5 parts by weight, relative to 100 parts by weight of the helical chiral polymer (A). It is more preferably ~ 3 parts by mass, further preferably 0.01 parts by mass to 2.8 parts by mass, further preferably 0.1 parts by mass to 2.8 parts by mass, and 0.5 It is especially preferable that it is 2 mass parts.
When the content is 0.01 parts by mass or more, the heat and humidity resistance is further improved.
Moreover, the transparency fall is suppressed more as the said content is 10 mass parts or less.

A preferred embodiment of the stabilizer (B) is 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 number average molecular weight of 200 to 900. (B1) and a stabilizer having two or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group in one molecule and having a weight average molecular weight of 1000 to 60000 ( B2) is used in combination. The weight average molecular weight of the stabilizer (B1) having a number average molecular weight of 200 to 900 is about 200 to 900, and the number average molecular weight and the weight average molecular weight of the stabilizer (B1) are almost the same value. .
When the stabilizer (B1) and the stabilizer (B2) are used in combination as the stabilizer (B), it is preferable to contain a large amount of the stabilizer (B1) from the viewpoint of improving the transparency.
Specifically, it is preferable that the stabilizer (B2) is in the range of 10 parts by mass to 150 parts by mass with respect to 100 parts by mass of the stabilizer (B1) from the viewpoint of achieving both transparency and wet heat resistance. The range of 30 to 100 parts by mass is more preferable, and the range of 50 to 100 parts by mass is particularly preferable.

The polymeric piezoelectric film used in this embodiment has one or more functional groups selected from the group consisting of carbodiimide groups, epoxy groups, and isocyanate groups, and has a weight average molecular weight of 200 to 60000. More preferably, (B) is contained in an amount of 0.01 to 10 parts by mass with respect to 100 parts by mass of the helical chiral polymer (A).
The polymer piezoelectric film used in the present embodiment has an internal haze with respect to visible light of 13% or less, and one or more functional groups selected from the group consisting of carbodiimide groups, epoxy groups, and isocyanate groups. Moreover, it is more preferable that the stabilizer (B) having a weight average molecular weight of 200 to 60,000 is contained in an amount of 0.01 to 2.8 parts by mass with respect to 100 parts by mass of the helical chiral polymer (A). Thereby, the polymer piezoelectric film is more excellent in the balance of piezoelectricity, transparency and wet heat resistance.

  Hereinafter, specific examples (stabilizers SS-1 to SS-3) of the stabilizer (B) will be shown.

Hereinafter, about the stabilizer SS-1 to SS-3, a compound name, a commercial item, etc. are shown.
-Stabilizer SS-1 The compound name is bis-2,6-diisopropylphenylcarbodiimide. The weight average molecular weight (in this example, simply equal to “molecular weight”) is 363. Examples of commercially available products include “Stabaxol I” manufactured by Rhein Chemie and “B2756” manufactured by Tokyo Chemical Industry Co., Ltd.
-Stabilizer SS-2 The compound name is poly (4,4'-dicyclohexylmethanecarbodiimide). As a commercially available product, “Carbodilite LA-1” manufactured by Nisshinbo Chemical Co., Ltd. may be mentioned as having a weight average molecular weight of about 2000.
-Stabilizer SS-3 The compound name is poly (1,3,5-triisopropylphenylene-2,4-carbodiimide). As a commercially available product, “Stabaxol P” manufactured by Rhein Chemie Co., Ltd. can be mentioned as having a weight average molecular weight of about 3000. Further, “Stabaxol P400” manufactured by Rhein Chemie is listed as having a weight average molecular weight of 20,000.

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

(Other ingredients)
The polymer piezoelectric film used in the present embodiment is a known resin typified by polyvinylidene fluoride, polyethylene resin and polystyrene resin, inorganic fillers such as silica, hydroxyapatite, and montmorillonite, as long as the effects of the present invention are not impaired. It may contain other components such as known crystal nucleating agents such as phthalocyanine.
When the polymer piezoelectric film contains components other than the helical chiral polymer (A), the content of components other than the helical chiral polymer (A) is 20% by mass or less based on the total mass of the polymer piezoelectric film. It is preferable that it is 10 mass% or less.

  The polymer piezoelectric film used in the present embodiment has the above-described helical chiral polymer (A) (that is, optical activity having a weight average molecular weight (Mw) of 50,000 to 1,000,000) as long as the effects of the present invention are not impaired. The helical chiral polymer having optical activity other than the helical chiral polymer (A)) having the above may be included.

  In addition, it is preferable that a polymeric piezoelectric film does not contain components other than the helical chiral polymer (A) which has optical activity from a transparency viewpoint.

-Manufacturing method of polymer piezoelectric film-
As a method for producing the polymer piezoelectric film used in the present embodiment, the crystallinity can be adjusted to 20% to 80%, and the product of the normalized molecular orientation MORc and the crystallinity can be adjusted to 40 to 700. The method is not particularly limited.
As this method, for example, a method including a step of forming a composition containing the helical chiral polymer (A) into a film (molding step) and a step of stretching the formed film (stretching step) is preferable. Can be manufactured. For example, the manufacturing method as described in Paragraph 0065-0099 of international publication 2013/054918 is mentioned.

(Molding process)
In the molding step, a composition containing the helical chiral polymer (A) and, if necessary, other components such as a stabilizer (B), is added to a melting point Tm (° C.) or higher of the helical chiral polymer (A). It is a process of heating to temperature and forming into a film shape. By this forming step, a film containing the helical chiral polymer (A) and other components such as a stabilizer (B) as required is 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) are respectively a differential scanning calorimeter (DSC). Is a value obtained from a melting endothermic curve when the temperature of the helical chiral polymer (A) is raised at a temperature rising rate of 10 ° C./min. The melting point (Tm) is a value obtained as a peak value of the endothermic reaction. The glass transition temperature (Tg) is a value obtained as the inflection point of the melting endothermic curve.

The said composition can be manufactured by mixing helical chiral polymer (A) and other components, such as a stabilizer (B) as needed.
The mixing may be melt kneading.
Specifically, the composition comprises a helical chiral polymer (A) and other components such as a stabilizer (B) if necessary, a melt kneader [for example, Labo Plast Mill manufactured by Toyo Seiki Seisakusho. ], And may be produced by melting and kneading by heating to a temperature equal to or higher than the melting point of the helical chiral polymer (A). In this case, in this step, the composition produced by heating and melting and kneading at a temperature equal to or higher than the melting point of the helical chiral polymer (A) was maintained at a temperature equal to or higher than the melting point of the helical chiral polymer (A). It is formed into a film shape in the state.
Examples of the melt kneading conditions 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 main molding step, as a method of molding the composition into a film, a melt extrusion molding, a press molding, an injection molding, a calendar molding, or a molding method using a casting method is used. Further, it may be formed into a film by a T-die extrusion method or the like.

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

In the forming step, the composition may be heated to the above temperature to form a film, and the resulting film may be quenched. The crystallinity of the film obtained in this step can be adjusted by rapid cooling.
Here, “rapid cooling” means cooling immediately after extrusion to at least the glass transition temperature Tg of the helical chiral polymer (A).
In the present embodiment, it is preferable that no other treatment is included between the forming into a film and the rapid cooling.

  The method of rapid cooling is a method of immersing the film in a coolant such as water, ice water, ethanol, ethanol or dry ice, methanol, or liquid nitrogen; spraying a liquid spray with low vapor pressure on the film and cooling the film by latent heat of vaporization Method; and the like.

Moreover, in order to cool a film continuously, it can also cool rapidly by making the metal roll and film controlled to the temperature below the glass transition temperature Tg of helical chiral polymer (A) contact.
Moreover, the frequency | count of cooling may be only once or may be 2 times or more.

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

  The thickness of the film (amorphous film or pre-crystallized film) obtained in the molding step is mainly determined by the thickness of the polymer piezoelectric film finally obtained and the draw ratio, but preferably 50 μm to It is 1000 micrometers, More preferably, it is about 100 micrometers-800 micrometers.

The pre-crystallized film is obtained by heat-treating an amorphous film containing the helical chiral polymer (A) and other components such as a stabilizer (B) as necessary, and crystallizing it. Can do.
The heating temperature T for pre-crystallization of the amorphous film is not particularly limited, but the glass transition temperature of the helical chiral polymer (A) is enhanced in terms of enhancing the piezoelectricity and transparency of the produced polymer piezoelectric film. It is preferable that the relationship between Tg and the following formula is satisfied and the crystallinity is set to 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-crystallization of the amorphous film can be appropriately set in consideration of the normalized molecular orientation MORc and crystallinity of the finally obtained polymer piezoelectric film.
The heating time is preferably 5 seconds to 60 minutes. As the heating time increases, the normalized molecular orientation MORc increases and the crystallinity tends to increase.
For example, when an amorphous film containing a polylactic acid polymer as the helical chiral polymer (A) is pre-crystallized, it is preferably heated at 20 ° C. to 170 ° C. for 5 seconds to 60 minutes.

  In order to pre-crystallize an amorphous film, for example, a cast roll adjusted to the above temperature range can be used. By using the electrostatic contact method described above, the polymer piezoelectric film is brought into close contact with the cast roll for preliminary crystallization to perform preliminary crystallization, and the thickness peak can be adjusted. For example, when adopting wire pinning that adheres the entire surface of the film, the peak of thickness can be adjusted by adjusting the position of the electrode, the material, the applied voltage, and the like.

(Stretching process)
The stretching step is a step of stretching a film (for example, a pre-crystallized film) obtained in the forming step mainly in a uniaxial direction. By this step, a polymer piezoelectric film having a large principal surface area can be obtained as a stretched film.
In addition, that the area of a main surface is large means that the area of the main surface of a polymeric piezoelectric film is 5 mm < ² > or more. Moreover, it is preferable that the area of a main surface is 10 mm < ² > or more.

  In addition, by stretching the film mainly in the uniaxial direction, the molecular chains of the helical chiral polymer (A) contained in the film can be aligned in one direction and aligned at a high density, and higher piezoelectricity can be obtained. Presumed to be obtained. As a method of stretching in a uniaxial direction in a continuous process, even in the case of longitudinal stretching in which the process flow direction (MD direction) matches the stretching direction, the direction perpendicular to the process flow direction (TD direction) matches the stretching direction. Lateral stretching may be used.

  The stretching temperature of the film is about 10 ° C. to 20 ° C. from the glass transition temperature of the film (or the helical chiral polymer (A) in the film) when the film is stretched only by a tensile force like stretching in a uniaxial direction. A high temperature range is preferred.

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

In the stretching process, when stretching (main stretching) for enhancing piezoelectricity, the molding process was performed in the direction intersecting (preferably orthogonally) the main stretching direction simultaneously or sequentially. A film (for example, a pre-crystallized film) may be stretched (also referred to as secondary stretching).
Here, “sequential stretching” refers to a stretching method in which stretching is performed in a uniaxial direction and then stretching in a direction intersecting with the stretching direction.
When secondary stretching is performed in the stretching step, the stretching ratio of the secondary stretching is preferably 1 to 3 times, more preferably 1.1 to 2.5 times, and 1.2 to 2.0. Double is more preferred. Thereby, the tearing strength of the polymer piezoelectric film can be further increased.

  In the stretching step, when the pre-crystallized film is stretched, preheating may be performed to facilitate stretching of the film immediately before stretching. This preheating is generally performed in order to soften the film before stretching and make it easy to stretch. Therefore, the preheating is performed under the condition that the film before stretching is not crystallized and hardened. It is normal. However, as described above, in the present embodiment, since pre-crystallization may be performed before stretching, the pre-heating may be performed together with pre-crystallization. Specifically, preheating and precrystallization can be performed by performing preheating at a temperature higher or longer than the normal temperature in accordance with the heating temperature and heat treatment time in the precrystallization step.

(Annealing process)
The manufacturing method of this embodiment may have an annealing process as needed.
The annealing step is a step of annealing (heat treatment) the film stretched in the stretching step (hereinafter also referred to as “stretched film”). By the annealing step, crystallization of the stretched film can be further advanced, and a polymer piezoelectric film having higher piezoelectricity can be obtained.
In addition, mainly when the stretched film is crystallized by annealing, the preliminary crystallization operation in the above-described forming step may be omitted. In this case, a film in an amorphous state can be selected as a film obtained in the molding process (that is, a film used in the stretching process).

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

  The method of annealing (heat treatment) is not particularly limited, but a method in which a stretched film is heated by contact with a heating roll or directly using a hot air heater or an infrared heater; a liquid in which the stretched film is heated (silicone oil) Etc.) and a method of heating by immersing in, etc .;

  The annealing is preferably performed while applying a certain tensile stress (for example, 0.01 MPa to 100 MPa) to the stretched film so that the stretched film does not sag.

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

The annealed stretched film (that is, the polymer piezoelectric film) is preferably rapidly cooled after annealing. The “rapid cooling” that may be performed in the annealing process is the same as the “rapid cooling” that may be performed in the above-described forming process.
The number of times of cooling may be only once, or may be two or more. Furthermore, annealing and cooling can be alternately repeated.

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

  The functional layer (X) is preferably an adhesive layer. In the present specification, “adhesion” is a concept including adhesion, and “adhesion layer” includes an adhesion layer. Below, the contact bonding layer which is one form of functional layer (X) is demonstrated.

The adhesive layer is an adhesive layer. As the adhesive layer, a double-sided tape (OCA; Optical Clear Adhesive) in which both surfaces are laminated with a separator can be used.
The adhesive layer can also be formed using a solvent-based, solvent-free, water-based or other adhesive coating solution, UV curable OCR (Optical Clear Resin), hot melt adhesive, or the like.

  As OCA, optical transparent adhesive sheet LUCIACS series (manufactured by Nitto Denko Corporation), highly transparent double-sided tape 5400A series (manufactured by Sekisui Chemical Co., Ltd.), optical adhesive sheet Optia series (manufactured by Lintec Corporation), high transparency adhesive Agent transfer tape series (manufactured by Sumitomo 3M Co., Ltd.), SANCUARY series (manufactured by Sanei Kaken Co., Ltd.), etc.

  Adhesive coating liquids (adhesive coating liquids) include SK Dyne series (manufactured by Soken Chemical Co., Ltd.), Fine Tack series (manufactured by DIC Corporation), Boncoat series, LKG series (manufactured by Fujikura Kasei Co., Ltd.), and Coponil series. (Manufactured by Nippon Synthetic Chemical Industry Co., Ltd.).

  As an adhesive layer, from the viewpoint of preventing heating of the polymer piezoelectric film, an adhesive coating is applied to an OCA adhesive layer, an adhesive layer formed using OCR, or a member other than the polymer piezoelectric film (for example, a release film described later). An adhesive layer formed by applying a liquid and an adhesive layer formed using a hot melt adhesive on a member other than the polymer piezoelectric film are preferred.

Although it does not specifically limit as a material of an contact bonding layer, It is preferable that resin is included.
Examples of the resin include acrylic resin, methacrylic resin, urethane resin, cellulose resin, vinyl acetate resin, ethylene-vinyl acetate resin, epoxy resin, nylon-epoxy resin, vinyl chloride resin, chloroprene. Rubber resin, cyanoacrylate resin, silicone resin, modified silicone resin, aqueous polymer-isocyanate resin, styrene-butadiene rubber resin, nitrile rubber resin, acetal resin, phenol resin, polyamide resin, polyimide resin, Examples include melamine resin, urea resin, bromine resin, starch resin, polyester resin, and polyolefin resin.

  The film thickness of the functional layer (X) is not particularly limited, but it is preferable that the thickness be 5 μm or more from the viewpoint of suppressing the adhesion of the functional layer (X) and reducing the transmittance. 7 μm to 100 μm is more preferable, 7 μm to 60 μm is further preferable, and 10 μm to 30 μm is particularly preferable.

-Acid value of 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 wet and heat environment, and 1 mgKOH / g or less. More preferably.
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). More preferably, it is more preferably 0.1 mgKOH / g or more.
In this specification, the acid value of the functional layer (X) refers to the amount (mg) of KOH required to neutralize the free acid in 1 g of the functional layer (X). The amount (mg) of KOH is measured by titrating the functional layer (X) dissolved or swollen in a solvent with a 0.005 M KOH (potassium hydroxide) ethanol solution using phenolphthalein as an indicator.

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

[Other layers]
In the film wound layer according to the present embodiment, the laminated film may have other layers between the polymer piezoelectric film and the functional layer (X). Other layers include, for example, an easy adhesion layer, a hard coat layer, a refractive index adjustment layer, an antireflection layer, an antiglare layer, an easy slip layer, an antiblock layer, a protective layer, an antistatic layer, a heat dissipation layer, an ultraviolet absorption layer, an antilayer Examples include a Newton ring layer, a light scattering layer, a polarizing layer, a gas barrier layer, and a hue adjustment layer. Moreover, as another layer, the layer which has two or more of the functions which the above-mentioned other layer each has may be sufficient, and two or more layers may be laminated | stacked in order. Among these, as the other layers, at least one layer of a refractive index adjusting layer, an easy adhesion layer, a hard coat layer, an antistatic layer, and an antiblock layer is preferable.
When other layers are provided on both principal surface sides of the polymer piezoelectric 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 inorganic substances such as metals and metal oxides; organic substances such as resins; composite compositions containing resins and fine particles. As resin, the hardened | cured material obtained by making it harden | cure with temperature or an active energy ray can also be utilized, for example. That is, a curable resin can also be used as the resin.

Examples of the curable resin include acrylic compounds, methacrylic compounds, vinyl compounds, allyl compounds, urethane compounds, epoxy compounds, epoxide compounds, glycidyl compounds, oxetane compounds, melamine compounds, and cellulose compounds. And at least one material (curable resin) selected from the group consisting of an ester compound, a silane compound, a silicone compound, a siloxane compound, a silica-acrylic hybrid compound, and a silica-epoxy hybrid compound.
Among these, acrylic compounds, epoxy compounds, and silane compounds are more preferable.
Examples of the metal include at least one selected from Al, Si, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, In, Sn, W, Ag, Au, Pd, Pt, Sb, Ta, and Zr. Or an alloy thereof.
Examples of the metal oxide include titanium oxide, zirconium oxide, zinc oxide, niobium oxide, antimony oxide, tin oxide, indium oxide, cerium oxide, aluminum oxide, silicon oxide, magnesium oxide, yttrium oxide, ytterbium oxide, and tantalum oxide. And at least one of these composite oxides.
Examples of the fine particles include metal oxide fine particles as described above, and resin fine particles such as a fluorine resin, a silicone resin, a styrene resin, and an acrylic resin. Furthermore, hollow fine particles having pores inside these fine particles are also included.
The average primary particle size of the fine particles is preferably from 1 nm to 500 nm, more preferably from 5 nm to 300 nm, and even more preferably from 10 nm to 200 nm, from the viewpoint of transparency. Scattering of visible light is suppressed when it is 500 nm or less, and secondary aggregation of fine particles is suppressed when it is 1 nm or more, which is desirable from the viewpoint of maintaining transparency.

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

  By forming other layers, defects such as die lines and dents on the surface of the polymer piezoelectric film are filled, and the appearance is improved. In this case, the smaller the refractive index difference between the polymer piezoelectric film and the other layers, the lower the reflection at the interface between the polymer piezoelectric film and the other layers and the more the appearance is improved.

As a method for forming the other layers described above, known methods that have been generally used can be used as appropriate. For example, vapor deposition, sputtering, ion plating, chemical vapor deposition (CVD), plating For example, dry coating methods and wet coating methods. 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 the other layer is formed from a curable resin, the other layer is formed by applying a coating liquid in which a material containing a curable resin, an additive, a solvent, or the like is dispersed or dissolved.

  Further, if necessary, the solvent (volatilizing resin, etc.) applied as described above is volatilized by drying the solvent or irradiated with heat or active energy rays (ultraviolet rays, electron beams, radiation, etc.). May be cured.

  Among the curable resins, active energy ray curable resins cured by irradiation with active energy rays (ultraviolet rays, electron beams, radiation, etc.) are preferable. By including the active energy ray curable resin, the production efficiency can be improved, and the performance degradation of the polymer piezoelectric film caused by the formation of other layers can be further suppressed.

  Moreover, when the said other layer is formed from curable resin, it is preferable that another layer contains the three-dimensional crosslinked resin which has a three-dimensional crosslinked structure from a viewpoint of raising a crosslinking density.

  As a means for producing a cured product having a three-dimensional crosslinked structure, a method using a monomer having three or more polymerizable functional groups (a monomer having three or more functional groups) as a curable resin, or a crosslinking having three or more polymerizable functional groups. Examples include a method using a crosslinking agent (a trifunctional or higher functional crosslinking agent), and a method using a crosslinking agent such as an organic peroxide as a crosslinking agent. A plurality of these means may be used in combination.

  Examples of the tri- or higher functional monomer include (meth) acrylic compounds having three or more (meth) acrylic groups in one molecule, and epoxy compounds having three or more epoxy groups in one molecule. .

  Further, “having three or more (meth) acrylic groups in one molecule” means having 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 3 or more.

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

In the case of the wet coating method, the polymer piezoelectric film may be stretched after the coating liquid has been applied to the original film before stretching of the polymer piezoelectric film, or the coating liquid may be applied after stretching the polymer piezoelectric film original film.
The thickness of the other layer (one layer) by the wet coating method is preferably in the range of several tens of nm to 10 μm.
In addition, various organic substances such as a refractive index adjusting agent, an ultraviolet absorber, a leveling agent, an antistatic agent, and an antiblocking agent, and inorganic substances can be added to the other layers according to the purpose.
From the viewpoint of improving the adhesion between the surface of the polymer piezoelectric film and other layers and the coating property on the surface of the polymer piezoelectric film, the polymer piezoelectric film can be treated by corona treatment, itro treatment, ozone treatment, plasma treatment, etc. The surface can also be treated.

[Release film]
In the film wound layer according to the present embodiment, the laminated film preferably further includes a release film disposed on the side opposite to the side on which the polymer piezoelectric film is disposed when viewed from the functional layer (X). . The film wound layer according to the present embodiment is obtained by winding a laminated film having a polymer piezoelectric film, a functional layer (X), and a release film in a roll shape. The length in the direction is preferably 10 m or more.

  As the material for the release film, a material having releasability (peelability) is preferably used. The release film may be a single film or a multilayer film composed of a plurality of layers. When the release film is a multilayer film composed of a plurality of layers, the release film is preferably formed in a structure in which a material having releasability is provided on the surface facing the adhesive layer. In this case, the release film may be formed in a structure including a base material and a material having releasability.

Specific examples of the releasable material include polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; olefin resins such as polyethylene, polypropylene, and polymethylpentene; polytetrafluoroethylene, polyfluorinated Fluorine resins such as vinylidene; vinyl resins such as polyvinyl chloride, styrene (meth) acrylic acid copolymer, styrene (meth) acrylic acid ester copolymer, polystyrene, and ethylene vinyl acetate;
In addition, examples of the material having releasability include polyurethane resin, polyimide resin, polyamide resin, silicone resin, acrylic silicone resin, melamine resin, alkyd resin, and wax resin.
The release film may be a single film of these or a multilayer film composed of a plurality of layers. In this case, the release film is preferably formed in a structure in which a material having releasability is provided on the surface facing the adhesive layer. Among these, a silicone resin, a fluororesin, a polyester resin, a polyolefin resin, an alkyd resin, and a wax resin are used as the material having releasability provided on the surface facing the adhesive layer in order to further improve the peelability from the adhesive layer. It is more preferable to use a silicone resin.

  Examples of silicone resins include those obtained by reacting silanol-functional dimethylpolysiloxane with methylhydrogenpolysiloxane or methylmethoxysiloxane in the presence of an organotin catalyst (thermal condensation reaction type); Or a reaction of methyl vinyl polysiloxane having vinyl groups at both ends and side chains with methyl hydrogen polysiloxane in the presence of a platinum-based catalyst (thermal addition reaction type); siloxane containing alkenyl group and mercapto group With photopolymerization agent added (ultraviolet curing type (radical addition type)); using the same platinum catalyst as thermal addition reaction type (ultraviolet curing type (hydrosilyl type)); containing (meth) acrylic group Siloxane and photopolymerization agent (UV curable type (radical polymerization type)); Siloxy containing epoxy group Onium salt photoinitiator (ultraviolet curable type (cationic polymerization type)); radical polymerizable group-containing siloxane (electron beam curable type, but no functional group, no photoinitiator) May also be included). Moreover, the form of the silicone resin can be appropriately selected from a solvent type, an emulsion type, a solventless type, and the like.

〔Base material〕
When the release film is formed in a structure including a substrate and a material having releasability, as the substrate, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene, polypropylene, polymethylpentene, triacetyl Examples of resins include cellulose, cellophane, rayon, polystyrene, polycarbonate, polyimide, polyamide, polyphenylene sulfide, polyetherimide, polyethersulfone, aromatic polyamide, and polysulfone. These uniaxially or biaxially stretched films, nonwovens, and foams Examples include the body. Moreover, as a base material, it can also select from glass, metal foil, ceramic, paper, etc.

  If necessary, the release film may be provided with a layer containing other materials such as an antistatic agent, an oligomer migration inhibitor, a smoothing agent, and an easy-adhesive agent on a layer other than the surface facing the adhesive layer. Good. For example, when the release film is formed in a structure including a base material and a material having releasability, the surface where the base material and the material having releasability face each other, and the releasability of the base material A layer containing the above-mentioned other material can be provided on either or both of the surface opposite to the surface facing the material having the above-described material.

  The film thickness of the release film is not particularly limited, but from the viewpoint of ease of release and handling, a range of 5 μm or more is preferable, a range of 10 μm to 100 μm is more preferable, and a range of 20 μm to 80 μm. Is more preferable, and the range of 30 μm to 80 μm is particularly preferable.

  In order to suitably peel the release film, it is preferable that the adhesive force between the adhesive layer and the polymer piezoelectric film is larger than the adhesive force between the adhesive layer and the release film.

As a method for forming the release film, a known method that has been generally used can be appropriately used. For example, the release film may be formed by extruding a resin for forming the release film with a film forming machine. When the release film is a multilayer film composed of a plurality of layers, each of the formed release films may be formed into a multilayer with an adhesive, and co-extruded to form a multilayer by a multilayer film forming machine. It may be formed.
Further, when the release film is a multilayer film composed of a plurality of layers formed in a structure including a base material and a material having releasability, the formed base material and the formed material having releasability May be formed in multiple layers with an adhesive, or may be formed into multiple layers by extrusion-forming a material having releasability on the formed substrate, or the material constituting the substrate and the mold release The material having the property may be co-extruded with a multilayer film forming machine to form a multilayer.

  Further, it may be formed by a wet coating method. For example, when a release film is formed by a wet coating method, a coating solution (release film coating solution) in which a material (resin, additive, etc.) for forming the release film is dispersed or dissolved is used as an adhesive layer. It can be formed by coating on top. In addition, when the release film is a multilayer film composed of a plurality of layers formed in a structure including a substrate and a material having releasability, it is formed by applying a release film coating solution onto the substrate. Can be made.

When a material having releasability is formed by a wet coating method, the material having releasability is used as a coating solution such as a solution or an emulsion, and this is used as a roll coater, comma coater, die coater, Mayer bar coater, reverse roll. You may form by apply | coating and drying on a contact bonding layer or a base material by well-known methods, such as a coater and a gravure coater.
In addition, when the release film is a multilayer film composed of a plurality of layers, the surface opposite to the surface facing the adhesive layer of the release film, or the surface opposite to the surface facing the adhesive layer of the release film. A surface activation treatment such as a corona discharge treatment, a flame treatment, an ozone treatment, or an anchor coating treatment using an anchor treatment agent may be applied to a substrate in contact with the surface. Since the adhesiveness of the multilayer film is improved by such treatment, it can be improved from the releasability with the adhesive layer.

<Method for producing film wound layer>
An embodiment of a method for producing a film wound layer according to the present invention will be described below. As a method for producing a film wound layer body, for example, a method in which a functional layer (X) is formed on a release film, and the functional layer (X) and a polymer piezoelectric film are bonded together to form a film wound layer body, Examples thereof include a method in which a functional layer (X) is formed on a polymer piezoelectric film, and the functional layer (X) and a release film are bonded together to form a film-wrapped layer.

[First embodiment]
The method for producing a rolled film body according to the first embodiment includes a step of forming a functional layer (X) by applying a functional layer forming agent for forming the functional layer (X) on the main surface of the release film. Forming a laminated film by bonding the functional layer (X) and the polymer piezoelectric film on the side opposite to the side where the release film is disposed as viewed from the functional layer (X) Winding the laminated film into a roll. In this manufacturing method, the functional layer (X) formed on the release film and the polymer piezoelectric film are bonded together to form a laminated film, and the formed laminated film is wound into a roll to form a film wound layer body. Manufacture.

-Formation of functional layer (X)-
The manufacturing method of the film winding layer body which concerns on this embodiment includes the process of providing the functional layer formation agent for forming a functional layer (X) in the main surface of a release film, and forming a functional layer (X). . At this time, a functional layer (X) may be formed by applying a film-like or sheet-like material (for example, the above-mentioned OCA) as a functional layer forming agent to the main surface of the release film to form a liquid functional layer. The functional layer (X) may be formed by applying an agent (for example, an adhesive coating solution) to the main surface of the release film and drying the applied functional layer forming agent. At this time, the drying temperature of the functional layer forming agent is preferably 50 ° C to 150 ° C, and more preferably 70 ° C to 130 ° C. Moreover, when providing functional layer (X) to the main surface of a release film, you may use a coating apparatus.

  Here, the functional layer (X) is preferably an adhesive layer, and the functional layer forming agent is preferably an adhesive. Therefore, an adhesive layer may be formed by applying an adhesive to the main surface of the release film. Examples of the adhesive include the above-mentioned OCA, solvent-based, solvent-free, and water-based adhesive coating solutions, UV curable OCR, hot melt adhesive, and the like.

-Formation of laminated film-
As described above, the method for manufacturing a film wound body according to the present embodiment, after forming the functional layer (X), is opposite to the side on which the release film is disposed as viewed from the functional layer (X). And a step of laminating the functional layer (X) and the polymer piezoelectric film to form a laminated film. Thereby, in the vertical direction of the main surface of the polymer piezoelectric film, a three-layer laminated film in which the polymer piezoelectric film, the functional layer (X), and the release film are laminated in this order is obtained.

  Furthermore, the functional layer (X) is formed on the main surface of another release film, and on the side opposite to the side where the release film is disposed when viewed from the functional layer (X), the functional layer (X ) And a polymer piezoelectric film constituting the three-layer laminated film formed as described above may be bonded together. Thereby, in the vertical direction of the main surface of the polymer piezoelectric film, a release film, a functional layer (X), a polymer piezoelectric film, a functional layer (X) and a release film are laminated in this order in a five-layer laminated film. Is obtained.

  The polymer piezoelectric film used for forming the laminated film may have the other layers described above disposed on at least one main surface. Thereby, another layer is arrange | positioned between functional layer (X) and a polymeric piezoelectric film at the time of formation of a laminated | multilayer film.

-Production of film wound layer-
The manufacturing method of the film winding layer body which concerns on this embodiment includes the process of winding the formed laminated film in roll shape. Thereby, a roll-shaped film winding layer body is obtained.
In the manufacturing method of this 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 formed functional layer (X) and the polymer piezoelectric film are formed. The film is pasted together. Therefore, there is no need to heat the polymer piezoelectric film, and elongation of the polymer piezoelectric film is suppressed. As a result, the dimensional change rate measured as described above can be 1.0% or less in the MD direction. Furthermore, since the film wound layer obtained by the production method of the present embodiment has high dimensional stability, the occurrence of cracks in the polymer piezoelectric film when heated is suppressed, and the moisture and heat resistance of the polymer piezoelectric film is suppressed. Excellent.

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

  First, in the film winding layer manufacturing apparatus 10, the release film 2 is pulled out from the roll-shaped release film 1 fixed to the roll body, and the extracted release film 2 is wound up by the other roll body. Then, the adhesive 3 is applied to the release film 2 between the rolls using the coating device 8. After the adhesive 3 is applied to the release film 2, the adhesive 3 is dried by a drying means (drying furnace) 9 to form the adhesive layer 4 on the main surface of the release film 2.

  In addition, the polymer piezoelectric film 6 is pulled out from the roll-shaped polymer piezoelectric film 5 fixed to the roll body, and the pulled-out polymer piezoelectric film 6 is bonded to the release film 2, and then the release film 2 and the roll body are used together. Wind up. Therefore, when the adhesive layer 4 is formed on the main surface of the release film 2, a laminated film is formed by bonding the adhesive layer 4 and the polymer piezoelectric film 6 together. And the film winding layered body 7 is obtained by winding the formed laminated film in roll shape.

  In the roll-to-roll continuous process, tension is generated in the film between the rolls in the film flow direction (MD direction). Therefore, when a polymer piezoelectric film containing an aliphatic polyester such as polylactic acid is provided between rolls and heat is applied to the polymer piezoelectric film when forming the adhesive layer, the polymer piezoelectric film has low heat resistance. Thus, the generated tension causes elongation in the polymer piezoelectric film, which may deteriorate the dimensional stability of the polymer piezoelectric film.

  On the other hand, in the roll-to-roll continuous process 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 elongation of the polymer piezoelectric film is suppressed, and the dimensional stability of the polymer piezoelectric film can be maintained.

[Second Embodiment]
Next, the manufacturing method of the film winding layered body which concerns on 2nd embodiment is demonstrated. Note that a description of matters common to the first embodiment is omitted. In the method for producing a film wound layer according to the second embodiment, the functional layer forming agent for forming the functional layer (X) is applied to at least one main surface of the polymer piezoelectric film, and the applied function is applied. The step of drying the layer forming agent at a temperature of 90 ° C. or lower to form the functional layer (X), and the side opposite to the side where the polymer piezoelectric film is disposed as viewed from the functional layer (X) And a step of bonding the functional layer (X) and the release film to form the laminated film, and a step of winding the formed laminated film into a roll. In this production method, after the functional layer forming agent is dried at a temperature of 90 ° C. or less to form the functional layer (X) on the polymer piezoelectric film, the functional layer (X) formed on the polymer piezoelectric film; A laminated film is formed by laminating with a release film, and the formed laminated film is wound into a roll to produce a film wound layer.

-Formation of functional layer (X)-
In the method for producing a film wound layer according to the present embodiment, a functional layer forming agent for forming the functional layer (X) is applied to at least one main surface of the polymer piezoelectric film, and the applied functional layer forming agent is applied. A step of drying at a temperature of 90 ° C. or less to form the functional layer (X). At this time, the drying temperature of the functional layer forming agent is preferably 50 ° C to 90 ° C, and more preferably 60 ° C to 80 ° C. Thereby, the dimensional stability of the polymer piezoelectric film can be more suitably maintained.

  Here, the functional layer (X) is preferably an adhesive layer, and the functional layer forming agent is preferably an adhesive. Therefore, an adhesive layer may be formed by applying an adhesive to the main surface of the polymer piezoelectric film. Examples of the adhesive include the above-mentioned OCA, solvent-based, solvent-free, and water-based adhesive coating solutions, UV curable OCR, hot melt adhesive, and the like.

-Formation of laminated film-
As described above, the method for producing a film wound layer according to the present embodiment is opposite to the side on which the polymer piezoelectric film is disposed as viewed from the functional layer (X) after the functional layer (X) is formed. On the side, a step of laminating the functional layer (X) and the release film to form a laminated film is included. When the functional layer (X) is formed on one main surface of the polymer piezoelectric film, the polymer piezoelectric film, the functional layer (X), and the release film are laminated in this order in the vertical direction of the main surface of the polymer piezoelectric film. A three-layer laminated film is obtained. When the functional layer (X) is formed on both main surfaces of the polymer piezoelectric film, in the vertical direction of the main surface of the polymer piezoelectric film, the release film, the functional layer (X), the polymer piezoelectric film, the functional layer ( A five-layer laminated film in which X) and the release film are laminated in this order is obtained.

-Production of film wound layer-
The manufacturing method of the film winding layer body which concerns on this embodiment includes the process of winding the formed laminated film in roll shape. Thereby, a roll-shaped film winding layer body is obtained.
In the manufacturing method of the present embodiment, when the functional layer (X) is formed on the polymer piezoelectric film, the functional layer forming agent on the polymer piezoelectric film is dried at a temperature of 90 ° C. or lower. Therefore, the elongation of the polymer piezoelectric film is suppressed as compared with the case where the functional layer forming agent on the polymer piezoelectric film is dried at a temperature higher than 90 ° C. to form the functional layer (X). As a result, the dimensional change rate measured as described above can be 1.0% or less in the MD direction. Furthermore, since the film wound layer obtained by the production method of the present embodiment has high dimensional stability, the occurrence of cracks in the polymer piezoelectric film when heated is suppressed, and the moisture and heat resistance of the polymer piezoelectric film is suppressed. Excellent.

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

  First, in the film winding layer manufacturing apparatus 20, the polymer piezoelectric film 12 is pulled out from the roll-shaped polymer piezoelectric film 11 fixed to the roll body, and the pulled-out polymer piezoelectric film 12 is wound up by the other roll body. Then, the adhesive 13 is applied to the polymer piezoelectric film 12 between the rolls using the coating device 18. After the adhesive 13 is applied to the polymer piezoelectric film 12, the adhesive 13 is dried at a temperature of 90 ° C. or less by a drying means (drying furnace) 19 to form the adhesive layer 14 on the main surface of the polymer piezoelectric film 12. To do.

  Further, after the release film 16 is pulled out from the roll-shaped release film 15 fixed to the roll body and the pulled-out release film 16 is bonded to the polymer piezoelectric film 12, the polymer piezoelectric film 12 is wound around the roll body. take. Therefore, when the adhesive layer 14 is formed on the main surface of the polymer piezoelectric film 12, a laminated film is formed by bonding the adhesive layer 14 and the release film 16 together. And the film winding layered body 17 is obtained by winding the formed laminated film in roll shape.

  In the roll-to-roll continuous process, tension is generated in the film between the rolls in the film flow direction (MD direction). Therefore, when a polymer piezoelectric film containing an aliphatic polyester such as polylactic acid is provided between rolls and heat is applied to the polymer piezoelectric film when forming the adhesive layer, the polymer piezoelectric film has low heat resistance. Therefore, depending on the applied heat, the tension generated may cause elongation of the polymer piezoelectric film, which may deteriorate the dimensional stability of the polymer piezoelectric film.

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

<Use of film wound layer>
Film wound body is speaker, headphone, touch panel, remote controller, microphone, underwater microphone, ultrasonic transducer, ultrasonic applied measuring instrument, piezoelectric vibrator, mechanical filter, piezoelectric transformer, delay device, sensor, acceleration sensor, impact Sensors, vibration sensors, pressure sensors, tactile sensors, electric field sensors, sound pressure sensors, displays, fans, pumps, variable focus mirrors, sound insulation materials, sound insulation materials, keyboards, acoustic equipment, information processing equipment, measurement equipment, medical equipment, etc. In particular, it is preferable to use a film-layered body in the field of various sensors from the viewpoint that the sensor sensitivity when used in a device can be maintained high.
Moreover, a film winding layered 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 EL panel, or the like can be used.
Moreover, a film winding layer body can also be used in combination with the touch panel (position detection member) of another system as a pressure-sensitive sensor. Examples of the detection method of the position detection member include an anti-film method, a capacitance method, a surface acoustic wave method, an infrared method, and an optical method.

  Hereinafter, although the film winding layered product of the present invention is explained more concretely by an example, the present invention is not limited to the following examples, unless the gist is exceeded.

<Production Example 1: Production of Polymer Piezoelectric Film>
As helical chiral polymer (A), NatureWorks LLC Corp. polylactic acid (PLA) (product ^name: Ingeo TM Biopolymer, brand: 4032D, weight average molecular weight Mw: 20 50,000) was prepared, to this polylactic acid 99 parts by weight Then, 1 part by mass of the following additive X (stabilizer (B)) was added and dry blended to prepare a raw material.
The prepared raw material is put into an extrusion molding machine hopper, extruded from a T die while being heated to 220 ° C. to 230 ° C., and brought into contact with a cast roll at 50 ° C. for 0.5 minutes to produce a pre-crystallized film having a thickness of 150 μm. Filmed (molding process). The crystallinity of the obtained pre-crystallized film was measured and found to be 4.91%.
The obtained pre-crystallized film was rolled to roll at 70 ° C. while being heated to 70 ° C., and was stretched at a stretching speed of 1650 mm / min, and uniaxially stretched in the MD direction up to 3.5 times to obtain a uniaxially stretched film (stretched) Process).
Thereafter, the uniaxially stretched film is subjected to annealing for 78 seconds on a roll heated to 130 ° C. by roll-to-roll (annealing step), then rapidly cooled with a roll set to 50 ° C., and further wound into a roll. Thus, a polymer piezoelectric film was obtained.

-Additive X (stabilizer (B))-
As additive X, a mixture of Stabaxol I (70 parts by mass) manufactured by Rhein Chemie and Carbodilite LA-1 (30 parts by mass) manufactured by Nisshinbo Chemical Co., Ltd. was used.
The detail of each component in the said mixture is as follows.
Stabaxol I ... bis-2,6-diisopropylphenylcarbodiimide (molecular weight (= weight average molecular weight): 363)
Carbodilite LA-1 Poly (4,4′-dicyclohexylmethanecarbodiimide) (weight average molecular weight: about 2000)

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

<Optical purity>
The optical purity of polylactic acid contained in the polymer piezoelectric film produced in Production Example 1 was measured as follows.
First, 1.0 g sample (the above-mentioned polymer piezoelectric film) is weighed into a 50 mL Erlenmeyer flask, and 2.5 mL of IPA (isopropyl alcohol) and 5 mL of 5.0 mol / L sodium hydroxide solution are added to the sample. It was set as the solution.
Next, the Erlenmeyer flask containing the sample solution 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.
The sample solution after stirring for about 5 hours was cooled to room temperature, neutralized by adding 20 mL of 1.0 mol / L hydrochloric acid solution, and the Erlenmeyer flask was sealed and mixed well.
Next, 1.0 mL of the sample solution stirred above was placed in a 25 mL volumetric flask, and a mobile phase having the following composition was added thereto to obtain 25 mL of HPLC sample solution 1.
5 μL of the obtained HPLC sample solution 1 was injected into the HPLC apparatus, and HPLC measurement was performed under the following HPLC measurement conditions. From the obtained measurement results, the area of the peak derived from the D-form of polylactic acid and the area of the peak derived from the L-form of polylactic acid were determined, and the amount of L-form and the amount of D-form were calculated. Based on the obtained results, the optical purity (% ee) was determined.
As a result, the optical purity was 97.0% ee. In Table 1 below, “LA” represents polylactic acid.
-HPLC measurement conditions-
・ Column Optical resolution column, SUMICHIRAL OA5000 manufactured by Sumika Chemical Analysis Co., Ltd.
・ HPLC apparatus, manufactured by JASCO Corporation, liquid chromatography, column temperature: 25 ° 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 (II) sulfate / IPA / water = 156.4 mg / 20 mL / 980 mL).
・ Mobile phase flow rate 1.0mL / min ・ Detector UV detector (UV254nm)

<Weight average molecular weight and molecular weight distribution>
Using gel permeation chromatograph (GPC), the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of polylactic acid were measured by the following GPC measurement method.
-GPC measurement method-
・ Measurement device Waters GPC-100
・ Column Showa Denko KK, Shodex LF-804
Sample Preparation The polymer piezoelectric film prepared in Production Example 1 was dissolved in a solvent [chloroform] at 40 ° C. 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 solvent (chloroform), a temperature of 40 ° C. and a flow rate of 1 mL / min, and the sample concentration in the sample solution separated by the column was measured with a differential refractometer. For the molecular weight of polylactic acid, a universal calibration curve was prepared using a polystyrene standard sample, and the weight average molecular weight (Mw) of polylactic acid was calculated.

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

<Crystallinity>
10 mg of the polymer piezoelectric film produced in Production Example 1 was accurately weighed and measured using a differential scanning calorimeter (DSC-1 manufactured by Perkin Elmer Co., Ltd.) at a temperature rising rate of 10 ° C./min. Got. The crystallinity was obtained from the obtained melting endotherm curve.

<Normalized molecular orientation MORc>
About the polymer piezoelectric film produced in Production Example 1, the normalized molecular orientation MORc was measured with a microwave molecular orientation meter MOA-6000 manufactured by Oji Scientific Instruments. The reference thickness tc was set to 50 μm.

<Internal haze>
The internal haze (hereinafter also referred to as internal haze (H1)) of the polymer piezoelectric film produced in Production Example 1 was obtained by the following method.
First, a laminate in which only a silicone oil (Shin-Etsu Chemical Co., Ltd., Shin-Etsu Silicone (trademark), model number: KF96-100CS) is sandwiched between two glass plates is prepared, and the haze in the thickness direction of the laminate is prepared. (Hereinafter referred to as haze (H2)) was measured.
Next, a laminate in which the polymer piezoelectric film having a surface uniformly coated with silicone oil is sandwiched between the two glass plates is prepared, and a haze in the thickness direction of the laminate (hereinafter, haze ( H3)) was measured.
Next, the internal haze (H1) of the polymer piezoelectric film was obtained by taking these differences as in the following formula.
Internal haze (H1) = Haze (H3) -Haze (H2)

Here, the measurement of haze (H2) and haze (H3) was respectively performed using the following apparatus under the following measurement conditions.
Measuring device: manufactured by Tokyo Denshoku Co., Ltd., HAZE METER TC-HIIIDPK
Sample size: 30mm width x 30mm length
Measurement conditions: Conforms to JIS-K7105 Measurement temperature: Room temperature (25 ° C.)

<Piezoelectric constant d ₁₄ (stress-charge method)>
The piezoelectric constant (specifically, the piezoelectric constant d ₁₄ (stress-charge method)) of the polymer piezoelectric film was measured according to the above-described “example of method for measuring the piezoelectric constant d ₁₄ by the stress-charge method”.

<Production Example 2: Preparation of adhesive coating solution>
Acrylic adhesive SK Dyne 1811L (manufactured by Soken Chemical Co., Ltd.) 10 kg, curing agent TD-75 (manufactured by Soken Chemical Co., Ltd.) 20 g, and 1 kg of toluene were mixed to obtain an adhesive coating solution.

<Production Example 3: Production of a polymeric piezoelectric film having a hard coat layer>
On one main surface of the polymer piezoelectric film produced in Production Example 1, an acrylic resin coating liquid (manufactured by Toyo Ink Co., Ltd., anti-block hard coat LIODURAS TYAB-014) was applied by roll-to-roll. The polymer piezoelectric film coated with the coating solution 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 similarly formed on the other main surface of the polymer piezoelectric film to obtain a polymer piezoelectric film having hard coat layers formed on both surfaces.

[Example 1]
The adhesive coating solution obtained in Production Example 2 is applied to the release surface of the release film (SP-PET O3-BU, manufactured by Mitsui Chemicals, Inc.) using a reverse gravure coating method and a line speed of 2.5 m / min. Applied. The release film coated with the adhesive coating solution was passed through a drying furnace at a temperature of 100 ° C. to form an adhesive layer. Furthermore, it rolls up, laminating the mold release surface (SP-PET O3-BU made by Mitsui Chemicals, Inc.) to the adhesive layer, and roll-up laminate A (mold film / adhesive layer / mold release). Film). And the roll-shaped laminated body A was stored at room temperature for 1 week, and hardening was completed. The thickness of the adhesive layer was 25 μm.
The release film on one side of the roll-shaped laminate A obtained as described above is peeled off with RtoR (roll-to-roll), and wound while laminating the polymer piezoelectric film produced in Production Example 1 on the adhesive layer. As a result, a roll-shaped laminate B (release film / adhesive layer / polymer piezoelectric film) was obtained.
Further, the release film on one side of another roll-shaped laminate A (release film / adhesive layer / release film) is peeled off by RtoR, and the polymer piezoelectric film of laminate B is exposed to the exposed adhesive layer. The film was rolled up while laminating the surface to obtain a roll-shaped laminate (film wound layer: release film / adhesive layer / polymer piezoelectric film / adhesive layer / release film).

[Example 2]
The adhesive coating solution obtained in Production Example 2 was applied to the polymer piezoelectric film produced in Production Example 1 by a reverse gravure coating method and a line speed of 2.5 m / min. The polymer piezoelectric film coated with the adhesive coating solution was passed through a drying furnace at a temperature of 70 ° C. to form an adhesive layer. Further, a laminate film C (release film / adhesive layer / polymer) was wound around the adhesive layer while laminating the release surface of the release film (SP-PET O3-BU manufactured by Mitsui Chemicals, Inc.). Piezoelectric film) was obtained.
Further, an adhesive layer is formed on the polymer piezoelectric film surface of the roll-shaped laminate C in the same manner as described above, and the release surface of the release film (SP-PET O3-BU manufactured by Mitsui Chemicals, Inc.) is laminated. The film was wound while being rolled to obtain a roll-shaped laminate (film winding layer: release film / adhesive layer / polymer piezoelectric film / adhesive layer / release film). Then, the roll-shaped laminate was stored at room temperature for 1 week to complete the curing. Each of the adhesive layers had a thickness of 25 μm.

Example 3
A roll-shaped laminate (film winding layer) was obtained in the same manner as in Example 1 except that the polymer piezoelectric film produced in Production Example 1 was changed to a polymer piezoelectric film having a hard coat layer produced in Production Example 3. Body: release film / adhesive layer / polymer piezoelectric film having hard coat layer / adhesive layer / release film).

Example 4
A roll-shaped laminate (film winding layer) was obtained in the same manner as in Example 2 except that the polymer piezoelectric film produced in Production Example 1 was changed to a polymer piezoelectric film having a hard coat layer produced in Production Example 3. Body: release film / adhesive layer / polymer piezoelectric film having hard coat layer / adhesive layer / release film). Then, the roll-shaped laminate was stored at room temperature for 1 week to complete the curing.

[Comparative Example 1]
Except that the temperature of the drying furnace was changed from 70 ° C. to 100 ° C., a roll-like laminate (film winding layer: release film / adhesive layer / polymer piezoelectric film / adhesive layer / A release film) was obtained. Then, the roll-shaped laminate was stored at room temperature for 1 week to complete the curing. Each of the adhesive layers had a thickness of 25 μm.

[Comparative Example 2]
The adhesive coating liquid obtained in Production Example 2 was hand-coated with the applicator on the polymer piezoelectric film produced in Production Example 1, and dried in an oven at a temperature of 100 ° C. to form an adhesive layer. Further, the release surface of the release film (SP-PET O3-BU manufactured by Mitsui Chemicals Tosero Co., Ltd.) is bonded to the adhesive layer with a roller, and a single wafer laminate (release film / adhesive layer / polymer). Piezoelectric film) was obtained.
Further, an adhesive layer is formed on the polymer piezoelectric film surface of the single-layer laminate in the same manner as described above, and the release surface of the release film (SP-PET O3-BU manufactured by Mitsui Chemicals, Inc.) is used as a roller. The laminate (sheet release film / adhesive layer / polymer piezoelectric film / adhesive layer / release film) was obtained. Then, the sheet stack was stored at room temperature for one week to complete the curing. Each of the adhesive layers had a thickness of 25 μm.

[Comparative Example 3]
A roll-shaped laminate (film winding layer) was prepared in the same manner as in Comparative Example 1 except that the polymer piezoelectric film produced in Production Example 1 was changed to a polymer piezoelectric film having a hard coat layer produced in Production Example 3. Body: release film / adhesive layer / polymer piezoelectric film having hard coat layer / adhesive layer / release film).

About the roll-shaped laminate obtained in Examples 1 to 4 and Comparative Examples 1 and 3 and the single-wafer laminate obtained in Comparative Example 2, the acid value of the adhesive layer, the MD dimensional change rate, the MD crack and the heat and moisture resistance Evaluation was performed as follows.
The evaluation results are shown in Table 2. In Table 2, “-” indicates no measurement data.

<Acid value of adhesive layer>
The release film is peeled from the laminate, 0.5 g of the exposed adhesive layer is dissolved in a solvent (chloroform), and titrated with 0.005M KOH (potassium hydroxide) ethanol solution using phenolphthalein as an indicator. Asked.

<MD dimensional change rate>
The polymer piezoelectric film obtained by removing the release film and the adhesive layer from the laminate is cut 50 mm in the stretching direction (MD direction) and 50 mm in the direction perpendicular to the stretching direction (TD direction), and is 50 mm × 50 mm. A rectangular film was cut out. This rectangular film was suspended in an oven set at 100 ° C. and annealed for 30 minutes. Thereafter, the dimensions of the film rectangular side length in the MD direction before and after the annealing treatment were measured with a high-precision digital length measuring machine (manufactured by Mitutoyo Corporation, Lightmatic VL-50AS). And according to the following formula, dimensional change rate (%) was calculated and dimensional stability was evaluated. A smaller dimensional change rate indicates higher dimensional stability.
(Expression) Dimensional change rate (%) = 100 × | (side length in MD direction before annealing) − (side length in MD direction after annealing) | / (side length in MD direction before annealing)

<MD crack>
The release films on both sides of the laminate were peeled, and Toray polyethylene terephthalate resin (PET) (brand: Lumirror T60-50) was attached to the exposed adhesive layer using a 2 kg roll. Thereby, it was set as the laminated structure by which five layers were laminated | stacked. That is, the laminated structure is composed of five layers of PET / adhesive layer / polymer piezoelectric film / adhesive layer / PET.
The laminated structure was punched into a 50 mm × 50 mm square with a pinnacle blade. And the obtained laminated structure (50 mm x 50 mm) was heated at 85 degreeC for 500 hours. Then, it was left to stand at room temperature for 24 hours, the presence or absence of the crack generation to MD direction was observed visually, and the following references | standards evaluated.
A: There is no crack in the polymer piezoelectric film of the laminated structure.
B: Cracks are generated in the polymer piezoelectric film of the laminated structure.

<Heat and heat resistance>
The weight average molecular weight of the polymeric piezoelectric film within 24 hours after the production of the laminate was measured (initial Mw). Next, a rectangular test piece of 50 mm in the longitudinal direction and 50 mm in the width direction is prepared from the laminate within 24 hours after production, and the test piece is suspended in a constant temperature and humidity chamber maintained at 85 ° C. and 85% RH. Hold for 120 hours. With respect to this test piece, the weight average molecular weight of the polymer piezoelectric film was measured (Mw after the wet heat resistance test), and the Mw maintenance rate represented by the following formula was evaluated according to the following criteria.
Formula: Mw retention rate = Mw after wet heat resistance test / initial Mw
〔Evaluation criteria〕
A: Mw maintenance rate ≧ 0.6
B: 0.6> Mw maintenance rate ≧ 0.35
C: Mw maintenance rate <0.35

In Examples 1 to 4, film wound layers having a MD dimensional change rate of the polymer piezoelectric film of 1.0% or less were produced. In this film-wrapped body, cracks do not occur in the polymer piezoelectric film when heated, and the polymer piezoelectric film has excellent moisture and heat resistance (particularly, Example 1).
On the other hand, in Comparative Examples 1 and 3, a film wound layer body having a MD dimensional change rate of the polymer piezoelectric film of 1.0% or more was produced. A crack occurred. In Comparative Example 2, a single-wafer laminate was produced, but the heat resistance of the polymer piezoelectric film was insufficient.

The disclosure of Japanese Patent Application No. 2015-040385 filed on March 2, 2015 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference, Incorporated herein by reference.

DESCRIPTION OF SYMBOLS 1,15 Roll-shaped release film 2,16 Release film 3,13 Adhesive 4,14 Adhesive layer 5,11 Roll-shaped polymeric piezoelectric film 6,12 Polymer piezoelectric film 7,17 Film wound layer body 8,18 Coating apparatus 9, 19 Drying means 10, 20 Film wound layer manufacturing apparatus

Claims (18)

Including a helical chiral polymer (A) having an optical activity with a weight average molecular weight of 50,000 to 1,000,000, crystallinity obtained by DSC method of 20% to 80%, and microwave transmission molecular orientation A polymer piezoelectric film in which the product of the normalized molecular orientation MORc and the crystallinity is 40 to 700 when the reference thickness measured by the meter is 50 μm;
A functional layer (X) provided on at least one main surface of the polymer piezoelectric film;
A laminated film having a roll shape,
Wherein the functional layer from the laminated film the polymer piezoelectric film obtained by removing the (X), the dimensional change ratio when heated at 100 ° C. 30 minutes state, and are 1.0% or less in the MD direction,
Total nitrogen content in the functional layer (X) is 0.05% to 10% by mass Ru film wound layer body.   The film winding layered product according to claim 1 whose acid value of said functional layer (X) is 10 mgKOH / g or less.   The film wound layer according to claim 1 or 2, wherein the functional layer (X) is an adhesive layer.   The film wound layer according to any one of claims 1 to 3, wherein the acid value of the functional layer (X) is 0.01 mgKOH / g or more.   The film wound layer body according to any one of claims 1 to 4, wherein the functional layer (X) is in contact with the polymer piezoelectric film. The laminated film has at least one layer of a refractive index adjusting layer, an easy adhesion layer, a hard coat layer, an antistatic layer, and an antiblock layer between the polymer piezoelectric film and the functional layer (X). The film winding layered product according to any one of claims 1 to 4 . The polymeric piezoelectric film comprises a stabilizer (B) having a weight average molecular weight of 200 to 60,000 having at least one functional group selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group. The film roll layered body according to any one of claims 1 to 6 , comprising 0.01 part by mass to 10 parts by mass with respect to 100 parts by mass of the molecule (A). The stabilizer (B) includes a stabilizer (B1) having a weight average molecular weight of 200 to 900 having one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group, and a carbodiimide group. , according to claim 7 including an epoxy group, and the weight average molecular weight having two or more one or more functional groups in one molecule selected from the group consisting of isocyanate groups stabilizers 1000-60000 and (B2), the Film winding layered body. The piezoelectric polymer film is 50% or less internal haze to visible light, and, at 25 ° C. stress - of claims 1 to 8 piezoelectric constant d ₁₄ measured by the charge method is 1 pC / N or more The film winding layered body according to any one of claims. The polymer piezoelectric film has an internal haze with respect to visible light of 13% or less, and a weight average molecular weight of 200 to 200 having at least one functional group selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group. 60000 of stabilizer (B), according to any one of the helical chiral polymer (a) 100 mass claims comprising 0.01 parts by 2.8 parts by mass per unit claim 1 to claim 9 Film winding layered body. The film according to any one of claims 1 to 10 , wherein the helical chiral polymer (A) is a polylactic acid polymer having a main chain containing a repeating unit represented by the following formula (1). Winding layered body.
The film winding layer according to any one of claims 1 to 11 , wherein the helical chiral polymer (A) has an optical purity of 95.00% ee or higher. The film winding layer according to any one of claims 1 to 12 , wherein a content of the helical chiral polymer (A) in the polymer piezoelectric film is 80% by mass or more. The laminated film is further of claims 1 to 13 having a release film disposed on the side opposite to the side where the piezoelectric polymer film as seen from the functional layer (X) is arranged The film winding layered body according to any one of claims. The film laminated layer according to claim 14 , wherein the laminated film has a length in the MD direction of 10 m or more. It is a manufacturing method of the film winding layered product according to claim 14 or 15 ,
Providing the functional layer forming agent for forming the functional layer (X) on the main surface of the release film to form the functional layer (X);
A step of bonding the functional layer (X) and the polymer piezoelectric film to form the laminated film on the side opposite to the side on which the release film is disposed when viewed from the functional layer (X). When,
A step of winding the formed laminated film into a roll,
The manufacturing method of the film winding layer body containing this. It is a manufacturing method of the film winding layered product according to claim 14 or 15 ,
A functional layer forming agent for forming the functional layer (X) is applied to at least one main surface of the polymer piezoelectric film, and the applied functional layer forming agent is dried at a temperature of 90 ° C. or lower to form a functional layer. Forming (X);
A step of bonding the functional layer (X) and the release film together to form the laminated film on the side opposite to the side where the polymeric piezoelectric film is disposed as viewed from the functional layer (X) When,
A step of winding the formed laminated film into a roll,
The manufacturing method of the film winding layer body containing this. The method for producing a film wound layer body according to claim 16 or 17 , wherein the functional layer (X) is an adhesive layer, and the functional layer forming agent is an adhesive.