JP2015186910A - laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate in which decrease in a production yield due to scratches on a polymeric piezoelectric film or intrusion of foreign substances is decreased in an intermediate process upon manufacturing a press-detection device or a device using the press-detection device.SOLUTION: The laminate includes the following polymeric piezoelectric film 10, a conductive layer (for example, an electrode 14A) disposed on one major surface of the polymeric piezoelectric film 10, and a protective film 16 that is removable and disposed on the other major surface of the polymeric piezoelectric film 10. The polymeric piezoelectric film 10 contains a helical chiral polymer (A) having optical activity and a weight average molecular weight of 50000 to 1000000, and has a crystallization degree of 20% to 80% obtained by a DSC method, in which a product of the crystallization degree and a normalized molecular orientation MORc measured by a microwave transmission type molecular orientation meter in a reference thickness of 50 μm is 40 to 700.

Description

  The present invention relates to a laminate.

  In recent years, polymer piezoelectric materials using a helical chiral polymer having optical activity (for example, polylactic acid polymer) 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).

  As a device using a polylactic acid-based polymer as a polymer piezoelectric member, for example, a pressure detection touch panel including a piezoelectric sheet made from polylactic acid as a pressure detection device has been proposed (see, for example, Patent Documents 2 to 5). ). Since the pressure detection touch panel can detect not only the two-dimensional position information on the touch panel but also the pressure with which the touch panel surface is pressed, the operation method of the touch panel can be extended to three dimensions.

  An electrode for detecting electric charges generated from a helical chiral polymer piezoelectric member is required for a pressure detection device using the helical chiral polymer piezoelectric member. There has been proposed a pressure detection device in which electrodes are directly formed on a surface.

JP-A-5-152638 International Publication No. 2010/143528 International Publication No. 2011/125408 International Publication No. 2012/049969 International Publication No. 2011/138903

  Here, when a pressure detection device using a helical chiral polymer piezoelectric member having an electrode, that is, a polymer piezoelectric film having a conductive layer (for example, a transparent conductive layer) is used as a device such as a pressure detection touch panel, the pressure detection device And a touch panel and other devices need to be stacked. Further, in the process of manufacturing the press detection device itself, it is necessary to provide a conductive layer on both sides of the polymer piezoelectric film to form a lead line (lead electrode).

  However, scratches or the like may occur in the polymer piezoelectric film during these intermediate steps. In addition, due to the stress during these intermediate steps, electric charges derived from piezoelectricity are generated on the surface of the polymer piezoelectric film, foreign matters such as dust adhere to the surface, and foreign matter may be involved in the product. And it became clear by examination of the present inventors that the yield of a product falls by these.

  Therefore, the present invention provides a laminate that suppresses a decrease in product yield due to generation of flaws in a polymer piezoelectric film or entrainment of foreign matters in an intermediate process when manufacturing a product such as a pressure detection device or a device using the same. It is to provide.

  The above problem is solved by the following means.

[1] A helical chiral polymer (A) having an optical activity of 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 reference thickness measured by a type molecular orientation meter is 50 μm;
A conductive layer provided on one main surface of the polymer piezoelectric film;
A peelable protective film provided on the other main surface of the polymer piezoelectric film;
A laminate having
[2] The laminate according to [1], wherein the conductive layer is patterned.
[3] Any one of [1] or [2], which has a functional layer between the polymer piezoelectric film and the protective film and at least one of the polymer piezoelectric film and the conductive layer. The laminated body as described in.
[4] The laminate according to [3], wherein the functional layer is at least one of a refractive index adjustment layer, an easy adhesion layer, a hard coat layer, an antistatic layer, and an antiblock layer.
[5] The laminate according to any one of [1] to [4], wherein the laminate having the protective film peeled has a thermal shrinkage rate of 2.0% or less in both the MD direction and the TD direction when heated at 150 ° C. for 30 minutes. .
[6] The laminate according to any one of [1] to [5], wherein the conductive layer is a transparent conductive layer.
[7] The polymeric piezoelectric film is no more than the internal haze is 5% 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] - [ [6] The laminate according to any one of [6].
[8] Any one of [1] to [7], 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). The laminated body as described in.

[9] The laminate according to any one of [1] to [8], wherein the helical chiral polymer (A) has an optical purity of 95.00% ee or more.
[10] The laminate according to any one of [1] to [9], wherein the content of the helical chiral polymer (A) is 80% by mass or more.
[11] The stabilizer (B) having a weight average molecular weight of 200 to 60000, wherein the polymer piezoelectric film has one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group. The laminate according to any one of [1] to [10], including 0.01 to 10 parts by mass with respect to 100 parts by mass of the helical chiral polymer (A).

  According to the present invention, there is provided a laminate that suppresses a decrease in the final product yield due to generation of scratches on a polymer piezoelectric film in an intermediate process or entrainment of foreign matters when a press detection device or a device using the same is manufactured. be able to.

It is sectional drawing which shows an example of the laminated body of this invention. It is process drawing which shows an example of the manufacturing method of the product using the laminated body of this invention. It is process drawing which shows an example of the manufacturing method of the product using the laminated body of this invention. It is process drawing which shows an example of the manufacturing method of the product using the laminated body of this invention.

The present invention will be described below.
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, the main surface of a film means the surface which opposes the thickness direction of a film. The “main surface” may be simply referred to as “surface”.

≪Laminated body≫
The laminate of the present invention includes a polymer piezoelectric film, a conductive layer provided on one main surface of the polymer piezoelectric film, and a peelable protective film provided on the other main surface of the polymer piezoelectric film. And having.
The polymer piezoelectric film includes a helical chiral polymer (A) having an optical activity having a weight average molecular weight of 50,000 to 1,000,000, and the crystallinity obtained by the DSC method is 20% to 80%. The product of the normalized molecular orientation MORc and the crystallinity is 40 to 700 when the reference thickness measured with a microwave transmission type molecular orientation meter is 50 μm.

In the laminate of the present invention, a protective film in which the other main surface side of the polymer piezoelectric film in the laminate body having a polymer piezoelectric film and a conductive layer provided on one main surface of the polymer piezoelectric film is peelable It is in a protected state. And in the process of manufacturing a product such as a pressure detection device or a device using the same, immediately after peeling the protective film from the laminate, various layers (adhesive layers) according to the purpose on the main surface side from which the protective film was peeled off Each product can be manufactured by forming a conductive layer, etc.).
For this reason, when manufacturing products, such as a press detection apparatus and a device using the same, it is possible to suppress a decrease in product yield due to the occurrence of scratches on the polymer piezoelectric film and the inclusion of foreign substances in the intermediate process.

Hereinafter, an example of the laminate of the present invention will be described with reference to the drawings.
For example, as illustrated in FIG. 1, the laminate 100 includes a polymer piezoelectric film 10. On one main surface of the polymer piezoelectric film 10, an intermediate layer 12A as a functional layer and an electrode 14A as a conductive layer are provided in this order. On the other hand, on the other main surface of the polymer piezoelectric film 10, an intermediate layer 12B as a functional layer and a protective film 16 are provided in this order.
The intermediate layers 12A and 12B are layers provided in the stacked body 100 as necessary. That is, the electrode 14 </ b> A as the conductive layer and the protective film 16 may each be provided in direct contact with the main surface of the polymer piezoelectric film 10.

  Next, an example of a method for manufacturing a product using the laminate 100 will be described. In addition, the manufacturing method of a product is not necessarily limited to the method demonstrated below, According to the target product, it implements suitably.

  First, as shown in FIG. 1, a polymer piezoelectric film 10, an intermediate layer 12 </ b> A and an electrode 14 </ b> A laminated on one main surface of the polymer piezoelectric film 10, and the other main surface of the polymer piezoelectric film 10. The laminated body 100A having the intermediate layer 12B laminated on is supplied to the manufacturing process of the product while being protected by the protective film 16.

  Next, as shown in FIG. 2A, for example, an extraction electrode 18A that is electrically connected to the electrode 14A is formed. Thereafter, the peelable release film 22A provided with the adhesive layer 20A and the laminate 100 are bonded so that the adhesive layer 20A and the electrode 14A face each other.

  Next, as shown in FIG. 2B, for example, the protective film 16 is peeled from the laminate 100. Then, the peelable release film 22B provided with the adhesive layer 20B and the laminate body 100A from which the protective film 16 has been peeled are bonded so that the intermediate layer 12B and the adhesive layer 20B face each other. For example, the peelable release film 22B provided with the adhesive layer 20B and the laminate body 100A may be bonded together while peeling the protective film 16 by a roll-to-roll method or the like.

  Next, as shown in FIG. 2C, a base material 24 provided with an electrode 14B as a conductive layer is prepared, and an extraction electrode 18B electrically connected to the electrode 14B is formed. Thereafter, the release film 22B bonded to the intermediate layer 12B side of the laminate body 100A is peeled off. Then, the laminate body 100A and the base material 24 are bonded together so that the adhesive layer 20B and the electrode 14B face each other. For example, the base material 24 provided with the electrode 14B and the laminate body 100A may be bonded to each other while peeling the release film 22B by a roll-to-roll method or the like.

  Although the product thus obtained is not shown, it is then used for manufacturing a product such as a pressure detection device or a device using the device.

  As described above, in the laminate 100, for example, immediately after the protective film 16 is peeled from the laminate 100, the peelable release film 22B provided with the adhesive layer 20B and the laminate from which the protective film 16 is peeled off. The body main body 100A is bonded so that the intermediate layer 12B and the adhesive layer 20B face each other. For this reason, generation | occurrence | production of the damage | wound of the polymeric piezoelectric film 10 and the entrapment of a foreign material are suppressed in the intermediate process which manufactures a product. As a result, a decrease in product yield due to these can be suppressed.

  In the example of the manufacturing method of the product using the laminated body 100, the electrode 14A of the laminated body 100 and the electrode 14B provided on the base material 24 are respectively provided with extraction electrodes 18A and 18B from the same direction. Can be formed. For this reason, the formation of the extraction electrodes 18A and 18B is simplified, and the productivity of the product can be increased.

  Hereinafter, each component of the laminated body of this invention is demonstrated. Note that the reference numerals are omitted. In addition, each component (adhesive layer, release film, lead electrode, base material) used in the manufacturing method of the product using the laminate 100 will be described.

<Polymer piezoelectric film>
As the polymer piezoelectric film (piezoelectric material), a predetermined polymer piezoelectric film containing the helical chiral polymer (A) having optical activity is applied.

[Helical Chiral Polymer with Optical Activity (A)]
The helical chiral polymer (A) is a helical chiral polymer having a weight average molecular weight of 50,000 to 1,000,000 and having optical activity.
Here, the “helical chiral polymer having optical activity” refers to a polymer having a helical structure and a molecular optical activity.
The helical chiral polymer (A) is a polymer having a weight average molecular weight of 50,000 to 1,000,000 among the above-mentioned “helical chiral polymers having optical activity”.

Examples of the helical chiral polymer (A) include polypeptides, cellulose derivatives, polylactic acid polymers, polypropylene oxide, poly (β-hydroxybutyric acid), and the like.
Examples of the polypeptide include poly (glutaric acid γ-benzyl), poly (glutaric acid γ-methyl), and the like.
Examples of the cellulose derivative include cellulose acetate and cyanoethyl cellulose.

  The helical chiral polymer (A) preferably has an optical purity of 95.00% ee or more, more preferably 96.00% ee or more, from the viewpoint of improving the piezoelectricity of the polymer piezoelectric film. More preferably, it is 99.00% ee or more, and even more preferably 99.99% ee or more. In particular, it is preferably 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.

Here, 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 optical purity of the helical chiral polymer (A) 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) ” Multiply by (100) the value divided by (the total amount of (A) L-form [mass%] and helical chiral polymer (A) D-form [mass%]] ". (Multiplied).

  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) are obtained by a method using high performance liquid chromatography (HPLC). Use the value obtained. Details of the specific measurement will be described later.

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

Examples of the polymer having the repeating unit represented by the formula (1) as a main chain include polylactic acid-based polymers.
Here, the polylactic acid polymer is “polylactic acid (polymer consisting only of repeating units derived from a monomer selected from L-lactic acid and D-lactic acid)”, “L-lactic acid or D-lactic acid, and L -A copolymer of a compound copolymerizable with lactic acid or D-lactic acid ", or a mixture of both.
Among the polylactic acid polymers, polylactic acid is preferable, and L-lactic acid homopolymer (PLLA) or D-lactic acid homopolymer (PDLA) is most preferable.

Polylactic acid is a polymer in which lactic acid is polymerized by an ester bond and connected for a long time.
It is known that polylactic acid can be produced by 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.
As polylactic acid, homopolymer of L-lactic acid, homopolymer of D-lactic acid, 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 A graft copolymer containing a polymer may be mentioned.

  Examples of the “compound copolymerizable with L-lactic acid or D-lactic acid” 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-hydroxycaprone Acids, hydroxycarboxylic acids such as 6-hydroxymethylcaproic acid and mandelic acid; cyclic esters such as glycolide, 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, un Polyvalent carboxylic acids such as candioic acid, dodecanedioic acid, terephthalic acid and the like; ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butane Diol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, neopentyl Polyhydric alcohols such as glycol, tetramethylene glycol and 1,4-hexanedimethanol; polysaccharides such as cellulose; aminocarboxylic acids such as α-amino acids;

  The “copolymer of L-lactic acid or D-lactic acid and a compound copolymerizable with the L-lactic acid or D-lactic acid” includes a block copolymer or a graft copolymer having a polylactic acid sequence capable of forming a helical crystal. Can be mentioned.

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

  Polylactic acid polymers are obtained by, for example, direct dehydration condensation of lactic acid described in JP-A-59-096123 and JP-A-7-033861; US Pat. No. 2,668,182 and A method of ring-opening polymerization using lactide, which is a cyclic dimer of lactic acid, as described in US Pat. No. 4,057,357.

  Furthermore, the polylactic acid polymer obtained by the above production methods has an optical purity of 95.00% ee or higher. For example, when polylactic acid is produced by the lactide method, the optical purity is improved by crystallization operation. It is preferable to polymerize lactide having an optical purity of 95.00% ee or higher.

-Weight average molecular weight-
The weight average molecular weight (Mw) of the helical chiral polymer (A) is 50,000 to 1,000,000 as described above.
When Mw of the helical chiral polymer (A) is 50,000 or more, the mechanical strength of the polymer piezoelectric film is improved. The Mw is preferably 100,000 or more, and more preferably 200,000 or more.
On the other hand, when the Mw 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 Mw is preferably 800,000 or less, and more preferably 300,000 or less.

  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 molecular weight distribution (Mw / Mn) of helical chiral polymer (A) point out the value measured by the following GPC measuring method using gel permeation chromatograph (GPC). Here, Mn is the number average molecular weight of the helical chiral polymer (A).

-GPC measuring device-
Waters GPC-100
-Column-
Made by Showa 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 can be used as the polylactic acid polymer that is an example of the helical chiral polymer (A).
Examples of commercially available products, PURAC Co. PURASORB (PD, PL), manufactured by Mitsui Chemicals, Inc. of LACEA (H-100, H- 400), NatureWorks LLC Corp. ^Ingeo TM Biopolymer, and the like.
When using a polylactic acid polymer as the helical chiral polymer (A), in order to make the weight average molecular weight (Mw) of the polylactic acid polymer 50,000 or more, the polylactic acid is obtained by the lactide method or the direct polymerization method. It is preferable to produce a polymer.

The polymer piezoelectric film may contain only one kind of the above-described helical chiral polymer (A), or may contain two or more kinds.
The content of the helical chiral polymer (A) in the polymer piezoelectric film (the total content in the case of two or more) is 80 mass relative to the total amount of the polymer piezoelectric film from the viewpoint of further increasing the piezoelectric constant. % Or more is preferable.

[Stabilizer]
The polymer piezoelectric film further 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 in one molecule. It is preferable to contain. Thereby, heat-and-moisture resistance can be improved more.

  As the stabilizer (B), “stabilizer (B)” described in paragraphs 0039 to 0055 of International Publication No. 2013/054918 pamphlet 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.
Commercially available products may be used as the carbodiimide compound, for example, manufactured by Tokyo Chemical Industry, B2756 (trade name), manufactured by Nisshinbo Chemical Co., Ltd., Carbodilite LA-1, manufactured by Rhein Chemie, Stabaxol P, Stabaxol P400, Stabaxol I (all Product name).

  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 molecular weight is within the above range, the stabilizer (B) is more easily moved, and the effect of improving 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 or two or more kinds.
When the polymeric piezoelectric film contains the stabilizer (B), the content of the stabilizer (B) is 0.01 parts by mass to 10 parts by mass with respect to 100 parts by mass of the helical chiral polymer (A). It is preferably 0.01 parts by mass to 5 parts by mass, more preferably 0.1 parts by mass to 3 parts by mass, and particularly preferably 0.5 parts by mass to 2 parts by mass. preferable.
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 ( A mode in which B2) is used in combination is exemplified. 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, it is preferable that a large amount of the stabilizer (B1) is contained 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. More preferably, it is in the range of 50 to 100 parts by mass.

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

Hereinafter, with respect to the stabilizers B-1 to B-3, compound names, commercial products, and the like are shown.
Stabilizer B-1 The compound name is bis-2,6-diisopropylphenylcarbodiimide. The weight average molecular weight (in this example, simply equal to “molecular weight”) is 363. Commercially available products include “Stabaxol I” manufactured by Rhein Chemie and “B2756” manufactured by Tokyo Chemical Industry.
Stabilizer B-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 B-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.

<Other ingredients>
The polymer piezoelectric film may contain other components as necessary.
Other components include known resins such as polyvinylidene fluoride, polyethylene resin and polystyrene resin; known inorganic fillers such as silica, hydroxyapatite and montmorillonite; known crystal nucleating agents such as phthalocyanine; other than stabilizer (B) And the like.
Examples of the inorganic filler and the crystal nucleating agent include components described in paragraphs 0057 to 0058 of International Publication No. 2013/054918.

<Physical properties of polymer piezoelectric film>
Polymeric piezoelectric film, it piezoelectric constant is large (preferably, the stress at 25 ° C. - that the piezoelectric constant d ₁₄ is 1 pC / N or more as measured by a charge method) is preferred. Furthermore, the polymer piezoelectric film is preferably excellent in transparency and longitudinal tear strength (that is, tear strength in a specific direction; the same applies hereinafter).

[Piezoelectric constant (stress-charge method)]
The piezoelectric constant of the polymer piezoelectric film is a value measured as follows.
First, the polymer piezoelectric film is cut to 150 mm in the direction of 45 ° with respect to the stretching direction (for example, MD direction) of the polymer piezoelectric film and 50 mm in the direction orthogonal to the direction of 45 °, and a rectangular test piece is formed. Make it. Next, the test piece obtained on the test stand of Showa vacuum SIP-600 is set, and Al is vapor-deposited on one surface of the test piece so that the deposition thickness of Al is about 50 nm. Next, Al is vapor-deposited in the same manner on the other surface of the test piece. As described above, an Al conductive layer is formed on both sides of the test piece.

  A direction in which a test piece of 150 mm × 50 mm (polymer piezoelectric film) having an Al conductive layer formed on both sides is formed by 45 ° with respect to the stretching direction (for example, MD direction) of the polymer piezoelectric film by 120 mm and 45 °. A rectangular film of 120 mm × 10 mm is cut out to 10 mm in a direction perpendicular to the film. 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 electric 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 Vm between terminals of the capacitor Cm (95 nF) is converted into a buffer amplifier. Measure through. 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, the greater the displacement of the film relative to the voltage applied to the polymer piezoelectric film, and conversely the greater the voltage generated for the force applied to the polymer piezoelectric film. It is useful as a piezoelectric film.
Specifically, the stress at 25 ° C. - piezoelectric constant _{d 14} measured by the charge method is preferably more than 1 pC / N, more preferably at least pC / N, more preferably more than 4Pc / N. In addition, the upper limit of the piezoelectric constant is not particularly limited, but from the viewpoint of balance such as transparency described later, in the case of a polymer piezoelectric film using a helical chiral polymer (optically active polymer) having optical activity, 50 pC / N The following is preferable, and 30 pC / N or less is more preferable.
Similarly, from the viewpoint of balance with transparency, the piezoelectric constant d14 measured by the resonance method is preferably ₁₅ pC / N or less.

  In the present specification, the “MD direction” is the direction in which the film flows (Machine Direction), that is, the stretching direction, and the “TD direction” is orthogonal to the MD direction and parallel to the main surface of the film. Transverse direction.

[Transparency (internal haze)]
The transparency of the polymer piezoelectric film can be evaluated by measuring internal haze.
The polymer piezoelectric film preferably has an internal haze of 5% or less for visible light, more preferably 2.0% or less, and more preferably 1.0% or less from the viewpoint of further improving transparency and longitudinal crack strength. Further preferred. The lower limit value of the internal haze of the polymer piezoelectric film is not particularly limited, and examples of the lower limit value include 0.01%.
Here, the internal haze of the polymer piezoelectric film refers to the haze excluding the haze due to the shape of the outer surface of the polymer piezoelectric film.
The internal haze of the polymer piezoelectric film was measured according to JIS-K7105 with respect to the polymer piezoelectric film having a thickness of 0.03 mm to 0.05 mm [TC Density Co., Ltd., TC- HIII DPK] is a value measured at 25 ° C., and details of the measuring method will be described in detail in Examples.

[Standardized molecular orientation MORc]
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).
Here, the molecular orientation degree MOR (Molecular Orientation Ratio) is measured by the following microwave measurement method. That is, a polymer piezoelectric film (for example, a film-shaped polymer piezoelectric material) is placed in a microwave resonant waveguide of a well-known microwave molecular orientation measuring device (also referred to as a microwave transmission type molecular orientation meter). It arrange | positions so that the surface (film surface) of a polymeric piezoelectric film may become perpendicular | vertical to the advancing direction of a wave. 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 1.0 to 15.0, more preferably 2.0 to 10.0, and 4.0 to 10.0. Further preferred.
If the normalized molecular orientation MORc is 1.0 or more, there are many optically active polymer molecular chains (for example, polylactic acid molecular chains) arranged in the stretching direction, and as a result, the rate of formation of oriented crystals increases. High piezoelectricity can be expressed.
If the normalized molecular orientation MORc is 15.0 or less, the longitudinal crack strength is further improved.
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.

  For example, when the polymer piezoelectric film is a stretched film, the normalized molecular orientation MORc is controlled by the heat treatment conditions (heating temperature and heating time) before stretching, the stretching conditions (stretching temperature and stretching speed), and the like. sell.

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, it is the lower limit of the preferred range of the normalized molecular orientation MORc. 2.0 can be converted to birefringence Δn 0.005. Further, 40, which is the lower limit of the preferred range of the product of the normalized molecular orientation MORc and crystallinity of the polymer piezoelectric film described later, is the product of the birefringence Δn and crystallinity of the polymer piezoelectric film of 0.1 Can be converted to

[Crystallinity]
The crystallinity of the polymer piezoelectric film is determined by the DSC method.
The degree of crystallinity of the polymer piezoelectric film according to the present invention is 20% to 80%. When the degree of crystallinity is 20% or more, the piezoelectricity of the polymer piezoelectric film is maintained high. When the degree of crystallinity is 80% or less, the transparency of the polymer piezoelectric film is maintained high, and when the degree of crystallinity is 80% or less, whitening and breakage hardly occur during stretching. Easy to manufacture piezoelectric film.
Therefore, the crystallinity of the polymer piezoelectric film is 20% to 80%, but the crystallinity is preferably 25% to 70%, more preferably 30% to 50%.

[Product of normalized molecular orientation MORc and crystallinity]
The product of the normalized molecular orientation MORc and the crystallinity of the polymer piezoelectric film is 40 to 700, preferably 75 to 680, more preferably 90 to 660, still more preferably 125 to 650, and particularly preferably 150 to 350. It is. When the above product is in the range of 40 to 700, the polymer piezoelectric film has a good balance between the piezoelectricity and transparency, and has high dimensional stability, and can be suitably used as a piezoelectric element described later.
In the polymer piezoelectric film according to the present invention, for example, the product can be adjusted to the above range by adjusting the crystallization and stretching conditions when the polymer piezoelectric film is produced.

[Shape and film thickness]
Although there is no restriction | limiting in particular in the shape of a polymeric piezoelectric film, A film shape is preferable.
The film thickness of the polymer piezoelectric film (for example, the film thickness of the polymer piezoelectric film in the case of a film shape) is not particularly limited, but is preferably 10 μm to 400 μm, more preferably 20 μm to 200 μm, and more preferably 20 μm to 100 μm. Is more preferable, and 20 μm to 80 μm is particularly preferable. However, when the polymer piezoelectric film is a multilayer film composed of a plurality of layers, the film thickness represents the thickness of the entire multilayer film.

<Conductive layer (electrode)>
The conductive layer is an electrode for detecting charges generated from the polymer piezoelectric film. The conductive layer may be provided on the entire surface of one surface of the polymer piezoelectric film, but is preferably patterned.

The conductive layer may be a transparent conductive layer or a non-transparent conductive layer. However, when a laminated body is used for a product such as a touch panel, the conductive layer is preferably a transparent conductive layer from the viewpoint of suppressing a decrease in transmittance and coloration.
Here, “transparent” means that the internal haze of the conductive layer is 20% or less and the total light transmittance is 80% or more.
The internal haze Hc of the conductive layer is calculated by the following formula.
Hc = H-Hp
H: Internal haze of laminated body of polymer piezoelectric film and conductive layer Hp: Internal haze of polymer piezoelectric film before formation of conductive layer or after removal of conductive layer However, a method for measuring the internal haze of the polymer piezoelectric film is As described above. The internal haze of the laminate is also measured by the same method as the internal haze of the polymer piezoelectric film.
Here, the total light transmittance of the conductive layer is also measured by the same method as the internal haze Hc of the conductive layer.

〔material〕
As a material for the conductive layer, a metal film, a conductive metal oxide film, a conductive polymer film, a conductive composition such as a metal or a resin containing a conductive metal oxide, or the like, as long as it exhibits conductivity, particularly It is not limited.
As a material for the transparent conductive layer, for example, indium tin oxide, indium oxide, tin oxide, zinc oxide, indium zinc oxide, or the like is preferably used from the viewpoint of suppressing a decrease in transmittance and coloration. Note that these oxides may be doped with a dopant such as a metal. These oxides may be in a crystalline state or an amorphous state. Moreover, silver nanowire, a carbon nanotube, graphene, or the resin composition containing them can also be used for the material of a transparent conductive layer.
The surface resistance of such a transparent conductive layer is preferably 2000 Ω / sq or less, more preferably 1000 Ω / sq, further preferably 500 Ω / sq, and particularly preferably 200 Ω / sq from the viewpoint of power consumption of the device.
On the other hand, as the material for the non-transparent conductive layer, gold, silver, platinum, copper, aluminum, carbon black, a composite thereof, or a paste material containing these is preferable.

[Film thickness]
The thickness of the conductive layer is preferably 5 nm to 500 nm, more preferably 10 nm to 200 nm, and still more preferably 10 nm to 60 nm, from the viewpoint of suppressing the decrease in transmittance and coloration.

(Formation method)
As a method for forming the conductive layer, known methods that have been generally used can be appropriately used. For example, vacuum deposition, sputtering, ion plating, CVD, electron beam deposition, sol-gel Method and wet coating method.

<Protective film>
As for a protective film, the film which has a base material and the adhesion layer laminated | stacked on one main surface of a base material is mentioned, for example. In addition, a protective film is good also as a single layer structure of a base material. In this case, the protective film is disposed on the surface of the polymer piezoelectric film or the functional layer (intermediate layer), for example, electrostatically or due to the adhesiveness of the protective film itself.

〔material〕
Examples of the base material include polyethylene resin, polypropylene resin, polyethylene / polypropylene copolymer resin, cyclic polyolefin, polyester resin, nylon resin, polyvinyl alcohol resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl chloride resin, and polycarbonate resin. , Polymethyl methacrylate resin, polyurethane resin, fluororesin, polyacrylonitrile, polybutene resin, polyimide resin, polyarylate resin, acetylcellulose resin and the like.
The base material may be a multilayer body of these resin layers.

  Examples of the material for the adhesive layer include ethylene-vinyl acetate copolymer (EVA) adhesives, acrylic adhesives, rubber adhesives, polyolefin adhesives (eg, polyethylene oligomer adhesives), and cellulose adhesives. (For example, glue), silicone adhesive, urethane adhesive, vinyl alkyl ether adhesive, polyvinyl alcohol adhesive, polyvinyl pyrrolidone adhesive, polyacrylamide adhesive, and the like. Among these, as the material for the adhesive layer, EVA adhesives, acrylic adhesives, and rubber adhesives are preferable from the viewpoint of moisture resistance and adhesiveness, and EVA adhesives are more preferable.

Here, examples of the adhesive polymer of the acrylic adhesive include, for example, an alkyl group having 1 to 10 carbon atoms such as 2-ethylhexyl acrylate, butyl acrylate, isooctyl acrylate, butyl methacrylate, propyl methacrylate, and the like ( A copolymer of a monomer mixture containing a (meth) acrylic acid ester and a functional group-containing unsaturated monomer such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, hydroxyethyl acrylate, and hydroxyethyl methacrylate. Preferably mentioned.
Preferable examples of the adhesive polymer of the rubber adhesive include styrene / butadiene random copolymer, styrene / isoprene block copolymer, and natural rubber.

〔Characteristic〕
The adhesive strength of the protective film (the adhesive strength of the protective film to the object (polymer piezoelectric film or functional layer) to which the protective film is bonded) is preferably 0.01 N / 50 mm to 1.5 N / 50 mm, preferably 0.02 N / 50 mm. -1.0 N / 50 mm is more preferable. When the adhesive strength of the protective film is within the above range, peeling of the protective film from the laminate is suppressed, and easy peeling of the protective film is easily realized when peeling the protective film.
The adhesive strength of the protective film is a value measured by pulling the protective film from the laminate having the protective film in a 180 ° direction at a speed of 300 mm / min with a tensile tester.

[Film thickness]
The thickness of the protective film is not particularly limited, but from the viewpoint of enhancing the protective function, the thickness is preferably 5 μm or more, more preferably 10 μm to 100 μm, even more preferably 20 μm to 80 μm, and even more preferably 30 μm to 30 μm. A range of 50 μm is particularly preferred.
Here, the film thickness of the substrate is preferably in the range of 9 μm to 99 μm, more preferably in the range of 19 μm to 79 μm, and still more preferably in the range of 29 μm to 49 μm. On the other hand, the thickness of the adhesive layer is preferably in the range of 1 μm to 20 μm, and more preferably in the range of 3 μm to 10 μm.

(Formation method)
As a method of forming the protective film, a known method that has been generally used can be appropriately used. For example, the protective film is formed by extruding a resin for forming the protective film with a film forming machine. Further, it may be formed by a wet coating method. When forming a protective film by the wet coat method, a coating liquid (coating liquid for protective film) in which a material (resin, additive, etc.) for forming the protective film is dispersed or dissolved is applied onto the polymer piezoelectric film. It is formed by coating.
Specifically, the material to be the base material and the material to be the adhesive layer are formed by extrusion using a multilayer film forming machine to form a protective film.
In addition, from the viewpoint of improving the releasability (peelability) of the protective film, the surface of the protective film can be treated by corona treatment, itro treatment, ozone treatment, plasma treatment, or the like.

  Examples of commercially available protective films include the PAC series from Sanei Kaken Co., Ltd., the 622 series from Sekisui Chemical Co., Ltd., the FM series from Daio Paper Industries Co., Ltd., and the V series from Sumilon Corporation.

<Functional layer (intermediate layer)>
The functional layer (intermediate layer) is a layer arbitrarily provided in at least one of the polymer piezoelectric film and the protective film and between the polymer piezoelectric film and the conductive layer in the laminate of the present invention.

〔material〕
The material for the functional 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. 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 selected from the group consisting of ester compounds, silane compounds, silicone compounds, siloxane compounds, silica-acrylic hybrid compounds, and silica-epoxy hybrid compounds.
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, tantalum oxide, Or these complex oxides are mentioned.

Examples of the fine particles include inorganic fine particles of metal oxide as described above; fine resin particles such as fluorine resin, silicone resin, styrene resin, and acrylic resin. Furthermore, examples of the fine particles include hollow fine particles having pores inside these inorganic fine particles or organic fine particles.
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.

[Film thickness]
Although the film thickness of a functional layer is not specifically limited, The range of 0.01 micrometer-10 micrometers is preferable.
When the thickness is 0.01 μm or more, for example, the functional layer exhibits functions such as a hard coat layer described later.
On the other hand, when the thickness is 10 μm or less, a large charge is generated in the electrode when the electrode (conductive layer) is provided in the laminate.

  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, in the case where the functional layer is a multilayer film composed of a plurality of functional layers, the above thickness represents the thickness of the entire multilayer film. The functional layer may be on both sides of the polymer piezoelectric film. Further, the refractive indexes of the functional layers may be different values.

[Type of functional layer (use)]
Examples of the functional layer include various functional layers. As functional layers, for example, easy adhesion layer, hard coat layer, refractive index adjustment layer, anti-reflection layer, anti-glare layer, easy slip layer, anti-block layer, protective layer, adhesive layer, antistatic layer, heat dissipation layer, ultraviolet absorption layer , An anti-Newton ring layer, a light scattering layer, a polarizing layer, a gas barrier layer, a hue adjusting layer, and the like. The functional layer may be a layer having two or more of these functions. Among these, as the functional layer, at least one of a refractive index adjusting layer, an easy adhesion layer, a hard coat layer, an antistatic layer, and an antiblock layer is preferable.
When the functional layers are provided on both main surfaces of the polymer piezoelectric film, the two functional layers may be the same functional layer or different functional layers.

  Further, by forming the functional layer, 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 functional layer, the more the reflection at the interface between the polymer piezoelectric film and the functional layer is reduced, and the appearance is further improved.

(Formation method)
As a method for forming the functional layer, known methods that have been generally used can be appropriately used. For example, dry methods such as vapor deposition, sputtering, ion plating, chemical vapor deposition (CVD), and plating can be used. Examples thereof include a coating method and a wet coating method. Examples of the wet coating method include a roll coating method, a spin coating method, a dip coating method, a bar coating method, and a gravure coating method.
For example, when the functional layer is a cured resin, the cured resin layer is formed by applying a coating liquid in which a material (curable resin, additive, solvent, etc.) for forming the cured resin layer is dispersed or dissolved. Is done.

  When the functional layer is a cured resin layer, if necessary, the solvent (such as a curable resin) applied as described above is volatilized by drying, or heat or active energy rays (ultraviolet rays, electrons, etc.) are dried. The curable resin is cured by irradiation.

  In addition, as a material contained in a cured resin layer, the active energy ray cured resin hardened | cured by irradiation of active energy rays (an ultraviolet ray, an electron beam, radiation, etc.) among the said curable resin is preferable. By including the active energy ray curable resin, the production efficiency is improved, and the performance degradation of the polymer piezoelectric film caused by the formation of the cured resin layer can be further suppressed.

  Moreover, it is preferable that the said cured resin 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. .

In the present specification, “(meth) acrylic group” represents at least one of an acrylic group and a methacrylic group.
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 cured resin 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 cured resin layer is immersed in a solvent for 24 hours. In particular, it can be presumed 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 new oily solvent such as toluene.

The use of the cured resin layer by the wet coat method can be applied to any of the above-listed layers. 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 (one layer) of the cured resin layer by wet coating is preferably in the range of several tens of nm to 10 μm.
Moreover, various organic substances and inorganic substances such as a refractive index adjusting agent, an ultraviolet absorber, a leveling agent, an antistatic agent, and an antiblocking agent can be added to the cured resin layer according to the purpose.
From the viewpoint of improving the adhesion between the surface of the polymer piezoelectric film and the cured resin layer 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.

[Relative permittivity]
The relative dielectric constant of the cured resin layer as the functional layer is preferably 1.5 or more, more preferably 2.0 or more and 20000 or less, and further preferably 2.5 or more and 10,000 or less.
When the relative dielectric constant is in the above range, a large charge is generated in the electrode when an electrode (conductive layer) is further provided on the cured resin layer in the laminate via an intermediate layer (other functional layer).

The relative dielectric constant of the cured resin layer is measured by the following method.
After forming a cured resin layer on one side of the polymer piezoelectric film, Al of about 50 nm is deposited on both sides of the laminate of the polymer piezoelectric film and the cured resin layer using Showa Vacuum SIP-600. A 50 mm × 50 mm film is cut out from this laminate. This test piece is connected to LCR METER 4284A manufactured by HEWLETT PACKARD, the capacitance C is measured, and the relative dielectric constant εc of the cured resin layer is calculated by the following equation.
εc = (C × d × 2.7) / (ε ₀ × 2.7 × S−C × dp)
d: thickness of cured resin layer, ε ₀ : vacuum dielectric constant, S: test piece area, dp: thickness of polymer piezoelectric film

[Internal haze of functional layer]
The internal haze of the functional layer is preferably 10% or less, more preferably 0.0% or more and 5% or less, and further preferably 0.01% or more and 2% or less.
When the internal haze is in the above range, excellent transparency is exhibited, and it can be effectively used as a touch panel, for example.

The internal haze Hc of the functional layer is calculated by the following formula.
Hc = H-Hp
H: Internal haze of laminate of polymer piezoelectric film and functional layer Hp: Internal haze of polymer piezoelectric film before functional layer formation or after functional layer is removed However, a method for measuring the internal haze of the polymer piezoelectric film is As described above. The internal haze of the laminate is also measured by the same method as the internal haze of the polymer piezoelectric film.

<Adhesive layer>
〔material〕
The adhesive layer is a layer having adhesiveness. As the adhesive layer, an adhesive layer of a double-sided tape (OCA; Optical Clear Adhesive) in which both surfaces are laminated with a separator can be used.
The pressure-sensitive adhesive layer can also be formed using a solvent-based, solvent-free, water-based or other pressure-sensitive 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 solutions include SK Dyne Series (manufactured by Soken Chemical Co., Ltd.), Fine Tack Series (manufactured by DIC Corporation), Bon Coat Series, LKG Series (manufactured by Fujikura Kasei Co., Ltd.), and Coponille Series (Nippon Gosei Chemical Co., Ltd. Company-made).

  As the adhesive layer, from the viewpoint of preventing the heating of the polymer piezoelectric film, an OCA adhesive layer, an adhesive layer formed using OCR, an adhesive layer formed by applying an adhesive coating solution to a member other than the polymer piezoelectric film An adhesive layer formed using a hot melt adhesive on a member other than the polymer piezoelectric film is preferred.

Although it does not specifically limit as a material of an adhesion 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, and cyanoacrylate resin. 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, melamine resin, urea resin, bromine Resins, starch resins, polyester resins, polyolefin resins and the like can be mentioned.

[Film thickness]
The thickness of the pressure-sensitive adhesive layer is not particularly limited, but the thickness is preferably in the range of 5 μm or more, more preferably in the range of 7 μm to 100 μm, from the viewpoint of maintaining the adhesion of the pressure-sensitive adhesive layer and suppressing the decrease in transmittance. 7 μm to 60 μm is more preferable, and a range of 10 μm to 30 μm is particularly preferable.

[Acid value of adhesive layer]
The acid value of the adhesive layer is preferably 0.01 mgKOH / g to 10 mgKOH / g, more preferably 0.05 mgKOH / g to 5 mgKOH / g, and 0.1 mgKOH / g from the viewpoint of suppressing the decrease in transmittance and coloration. More preferred is ˜1 mg KOH / g. By maintaining the acid value of the adhesive layer at 0.01 mg KOH / g to 10 mg KOH / g, the layer having the acid value with the polymer piezoelectric film while maintaining the stability of the polymer piezoelectric film (particularly heat and moisture resistance) It is possible to increase the adhesion with.
In the laminate of the present invention, the acid value of the adhesive layer refers to the amount (mg) of KOH required to neutralize the free acid in 1 g of the adhesive layer. The amount (mg) of KOH is measured by titrating an adhesive layer dissolved or swollen in a solvent with a 0.005 M KOH (potassium hydroxide) ethanol solution using phenolphthalein as an indicator.

<Release film>
〔material〕
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, polyvinyl chloride, styrene (meth) acrylic acid copolymers, styrene (meth) acrylic acid ester copolymers, vinyl resins such as polystyrene and ethylene vinyl acetate; and the like.
In addition, polyurethane resin, polyimide resin, polyamide resin, silicone resin, acrylic silicone resin, melamine resin, alkyd resin, wax resin, and the like can be given.
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 a 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 a multilayer film composed of a plurality of layers, as a substrate, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene, polypropylene, polymethylpentene, triacetyl cellulose, cellophane, rayon, polystyrene, polycarbonate, Examples thereof include resins such as polyimide, polyamide, polyphenylene sulfide, polyetherimide, polyethersulfone, aromatic polyamide, and polysulfone, and these include uniaxially or biaxially stretched films; nonwoven fabrics; foams and the like. The substrate can be selected from glass, metal foil, ceramic, paper and the like.

[Other materials]
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 layer 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-described other material can be provided on either or both of the surface opposite to the surface facing the material having the above.

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

[Peelability of release film (release property)]
In order to make the release film peelable, the adhesive force between the adhesive layer and the polymer piezoelectric film is preferably larger than the adhesive force between the adhesive layer and the release film.

(Formation method)
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 base material, or the material constituting the base material 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 liquid (release film coating liquid) 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 liquid, 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 an adhesion layer or a base material by well-known methods, such as a coater and a gravure coater.
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 base material in contact with the surface. Since the adhesiveness of the multilayer film is improved by such treatment, it can be improved from the release from the adhesive layer.

<Extraction electrode>
Constituent components and forming methods of the extraction electrode include the same constituent components and forming method as the conductive layer (electrode).
Examples of the extraction electrode include FPC (flexible printed circuit board).

  Examples of the connection method of the extraction electrode include a method of connecting to the end of the conductive layer (electrode) using ACF (anisotropic conductive film), ACP (anisotropic conductive paste), solder, or the like. It is done.

<Base material>
Examples of the material of the base material that is provided with the conductive layer (electrode) and is bonded to the laminate after peeling off the protective film include, for example, polyethylene resin, polypropylene resin, polyethylene / polypropylene copolymer resin, cyclic polyolefin resin, polyester resin, Nylon resin, polyvinyl alcohol resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl chloride resin, polycarbonate resin, polymethyl methacrylate resin, polyurethane resin, fluororesin, polyacrylonitrile, polybutene resin, polyimide resin, polyarylate resin, acetylcellulose resin Etc.

  The thickness of the substrate is preferably 1 μm to 100 μm, more preferably 5 μm to 80 μm, and even more preferably 10 μm to 50 μm.

<Physical properties of the laminate>
[Thermal dimensional stability (thermal shrinkage)]
In the laminate of the present invention, the thermal shrinkage rate when heated at 150 ° C. for 30 minutes with the protective film peeled is preferably 2.0% or less in both the MD direction and the TD direction.
In the laminated body, the whole or a part of the laminated body may be heated in the step of crystallizing the formed conductive layer or the step of connecting the conductive layer and the external circuit when using the laminated body as a device. However, when the thermal contraction rate is large, the formed electrode layer may be damaged or misaligned, poor connection with the extraction electrode, or the laminate may be deformed. Therefore, it is preferable that the thermal contraction rate is low.
The thermal dimensional stability of the laminate is evaluated by measuring the thermal shrinkage rate when treated at 150 ° C. for 30 minutes in the MD direction and the TD direction, respectively. Specifically, the thermal contraction rate of the laminate is calculated by the following method.

  The heat shrinkage rate of the laminate was determined by taking a sample piece (sample piece from which the protective film had been peeled) cut into a 100 mm square in the MD direction and a 100 mm square in the TD direction for 30 minutes in an oven at 150 ° C., and taking it out of the oven. Then, the dimension of MD direction and TD direction of a sample piece is measured at room temperature. Using the measured value, the heat shrinkage rate is calculated from the following formula.

  Heat shrinkage rate = 100 × (size of sample piece before standing in oven−size of sample piece measured at room temperature after standing in oven) / size of sample piece before standing in oven

<Use of laminate>
The laminate of the present invention includes a speaker, a headphone, a touch panel, a remote controller, a microphone, an underwater microphone, an ultrasonic transducer, an ultrasonic applied measuring instrument, a piezoelectric vibrator, a mechanical filter, a piezoelectric transformer, a delay device, a sensor, an acceleration sensor, Shock sensor, vibration sensor, pressure sensor, tactile sensor, electric field sensor, sound pressure sensor, display, fan, pump, variable focus mirror, sound insulation material, sound insulation material, keyboard, sound equipment, information processing machine, measurement equipment, medical equipment It can be used in various fields such as.
Moreover, the laminated body of this invention can also be used as a touchscreen combined with the display apparatus. As the display device, for example, a liquid crystal panel, an organic EL panel, or the like can be used.
Moreover, the laminated body of this invention can also be used in combination with the touch panel (position detection member) of another system as a pressure 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.

Moreover, a laminated body can be repeatedly stacked and used as a laminated piezoelectric element. As an example, a laminate is repeatedly stacked, and finally the surface of the laminate that is not covered with an electrode (conductive layer) is covered with an electrode (conductive layer).
Further, when the laminated piezoelectric element includes polymer piezoelectric films in a plurality of laminated bodies, if the optical activity of the helical chiral polymer (A) contained in the polymer piezoelectric film of a certain layer is L, the other layers The helical chiral polymer (A) contained in the polymer piezoelectric film may be L-form or D-form. The arrangement of the polymer piezoelectric film can be appropriately adjusted according to the use of the piezoelectric element.

  For example, the first layer of the polymer piezoelectric film containing the L-form helical chiral polymer (A) as the main component contains the second high-density polymer containing the L-form helical chiral polymer (A) as the main component via the electrode. When laminated with a molecular piezoelectric film, the uniaxial stretching direction (main stretching direction) of the first polymer piezoelectric film intersects, preferably orthogonal, with the uniaxial stretching direction (main stretching direction) of the second polymer piezoelectric film. This is preferable because the direction of displacement of the first polymer piezoelectric film and the second polymer piezoelectric film can be made uniform, and the piezoelectricity of the entire laminated piezoelectric element is enhanced.

  On the other hand, the first layer of the piezoelectric polymer film containing the L-form helical chiral polymer (A) as the main component contains the second high-density polymer containing the D-form helical chiral polymer (A) as the main component via the electrode. When laminated with a molecular piezoelectric film, the uniaxial stretching direction (main stretching direction) of the first polymeric piezoelectric film is substantially parallel to the uniaxial stretching direction (main stretching direction) of the second polymeric piezoelectric film. It is preferable that the first polymer piezoelectric film and the second polymer piezoelectric film can be arranged in the same direction, and the piezoelectricity of the entire laminated piezoelectric element is enhanced.

  The piezoelectric element using the laminate of the present invention can be applied to the above-described various piezoelectric devices such as speakers and touch panels. In particular, a piezoelectric element provided with a transparent electrode is suitable for application to a speaker, a touch panel, an actuator, and the like.

<Method for producing laminate>
As an example of the manufacturing method of a laminated body, the manufacturing method of the polymeric piezoelectric film and the laminated body which has a conductive layer and a protective film on both surfaces of a polymeric piezoelectric film are demonstrated.
First, a polymer piezoelectric film is manufactured. Examples of a method for producing a polymer piezoelectric film include a method of crystallizing and stretching (any of which may be first) on an amorphous sheet containing the optically active polymer described above. .

  The non-crystalline sheet is an optically active polymer (helical chiral polymer (A)) alone or a mixture containing the optically active polymer heated to a temperature equal to or higher than the melting point Tm of the optically active polymer, The sheet obtained by rapid cooling is shown. An example of the rapid cooling temperature is 50 ° C.

In the method for producing a polymer piezoelectric film, the optically active polymer (polylactic acid polymer or the like) may be used alone as a raw material for the polymer piezoelectric film (or amorphous sheet). Using a mixture of two or more optically active polymers (such as polylactic acid-based polymers) described above, or a mixture of at least one optically active polymer described above and at least one other component Also good.
The above mixture is preferably a mixture obtained by melt kneading.
Specifically, for example, when mixing an optically active polymer, or when mixing other components (for example, the above-described inorganic filler and crystal nucleating agent) with one or more types of optically active polymer, the optical activity to be mixed The polymer (along with other components as required) is used for 5 to 20 minutes under the conditions of mixer rotation speed 30 rpm to 70 rpm, 180 ° C. to 250 ° C. using a melt kneader (manufactured by Toyo Seiki Co., Ltd., Laboplast mixer). By melt-kneading, a blend of a plurality of types of optically active polymers or a blend of optically active polymers and other components such as inorganic fillers can be obtained.

  The polymer piezoelectric film is also manufactured by a manufacturing method including a step of stretching a sheet containing an optically active polymer (preferably an amorphous sheet) mainly in a uniaxial direction and an annealing treatment step in this order. it can.

In addition, the polymer piezoelectric film is included in the polymer piezoelectric film from the viewpoint of further improving the adhesion between the polymer piezoelectric film and the intermediate layer, and further improving the moisture heat resistance and tear strength of the polymer piezoelectric film. You may adjust the ratio of the acrylic terminal of the polymer to be prepared.
Specifically, the polymer piezoelectric film was obtained by measuring a ¹ H-NMR spectrum of a solution obtained by dissolving 20 mg of the polymer piezoelectric film in 0.6 mL of deuterated chloroform, and measuring the measured ¹ H-NMR spectrum. Based on the following formula (X), when the ratio of the acrylic terminal of the polymer contained in the polymer piezoelectric film is determined, the ratio of the acrylic terminal of the polymer is 2.0 × 10 ⁻⁵ to 10 −10. It may be 0.0 × 10 ⁻⁵ .
Ratio of acrylic end of the polymer = integral value of peak derived from acrylic end of polymer / integral value of peak derived from methine in the main chain of the polymer Formula (X)
The polymeric piezoelectric film may contain at least one colorant in order to adjust the hue. Examples of the colorant include a bluing agent for correcting yellowishness.

Next, a conductive layer is formed on one main surface of the polymer piezoelectric film.
After the conductive layer is formed on the polymer piezoelectric film by a known method (vacuum deposition method, sputtering method, ion plating method, CVD method, electron beam deposition method, sol-gel method, wet coating method) Using a pattern forming means (masking, lithography, etc.), a part of the conductive layer can be etched with acid or alkali. Moreover, after masking a part of the polymer piezoelectric film with a pattern mask, a mending tape, or the like, a conductive layer can be formed on a part of the polymer piezoelectric film by a known method. Moreover, the composition containing the material of the conductive layer can be partially applied to the polymer piezoelectric film by a part coat method, a screen printing method, a gravure printing method, or the like.

Next, a protective film is formed on the other main surface of the polymer piezoelectric film.
The protective film can be formed by, for example, laminating with a polymer piezoelectric film provided with a conductive layer by a known method such as a roll-to-roll method.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.

<Production Example 1: Production of Polymer Piezoelectric Film (Polylactic Acid Film: PLA Film)>
As helical chiral polymer (A), NatureWorks LLC Corp. polylactic acid polymer (product ^name: Ingeo TM Biopolymer, brand: 4032D, weight average molecular weight Mw: 20 million in the melting point (Tm): 166 ° C., a glass transition temperature ( Tg): 57 ° C. to 60 ° C.) was prepared. And 1.0 mass part of additive X (stabilizer (B)) mentioned later was added with respect to 100 mass parts of polylactic acid-type polymers, and it dry-blended and produced the 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 50 ° C. cast roll for 0.3 minutes to produce a 150 μm thick pre-crystallized sheet. Filmed (pre-crystallization step). The crystallinity of the pre-crystallized sheet was measured and found to be 6%.
The obtained pre-crystallized sheet was stretched at a stretching speed of 3 m / min with a roll-to-roll while heating to 70 ° C., and uniaxially stretched in the MD direction up to 3.5 times (stretching step). The thickness of the obtained film was 47.2 μm.
Thereafter, the uniaxially stretched film was subjected to annealing treatment with a roll to roll on a roll heated to 145 ° C. for 15 seconds to produce a polymer piezoelectric film (annealing treatment step).

-Additive X (stabilizer (B))-
As additive X, a mixture of Stabaxol P400 (20 parts by mass) manufactured by Rhein Chemie, Stabaxol I (50 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)
Stabaxol P400: poly (1,3,5-triisopropylphenylene-2,4-carbodiimide) (weight average molecular weight: 20000)
Carbodilite LA-1: poly (4,4′-dicyclohexylmethanecarbodiimide) (weight average molecular weight: about 2000)

<Measurement of physical properties of helical chiral polymer (A)>
The optical purity of the helical chiral polymer (A) was measured by the following method. Moreover, the weight average molecular weight and molecular weight distribution were measured by the above-mentioned method. The results are shown in Table 1.

[Optical purity]
The optical purity of the helical chiral polymer (A) (polylactic acid) contained in the polymer piezoelectric film 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 equipment: JASCO Corporation liquid chromatography column temperature: 25 ℃
-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)

<Measurement of physical properties of polymer piezoelectric film>
About the said polymeric piezoelectric film, melting | fusing point Tm, crystallinity, and internal haze were measured with the following method. In addition, the piezoelectric constant (stress-charge method) and the normalized molecular orientation MORc were measured by the methods described above. The results are shown in Table 1.

[Melting point Tm and crystallinity]
10 mg of the polymer piezoelectric film 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 to obtain a melting endotherm curve. The melting point Tm and the crystallinity were obtained from the obtained melting endotherm curve.

[Internal haze]
The internal haze (hereinafter also referred to as internal haze (H1)) of the polymer piezoelectric film 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.)

<Example 1>
One main surface of the polymer piezoelectric film produced in Production Example 1 is sputtered by roll-to-roll using indium oxide containing 36% by mass of tin oxide as a target, and one main surface of the polymer piezoelectric film is obtained. An ITO layer having an actual thickness of 15 nm and a refractive index of 1.95 was formed as a conductive layer (electrode) on the part.
Furthermore, the main surface of the polymer piezoelectric film opposite to the surface on which the conductive layer is formed is a roll-to-roll using a laminator, and a protective film (PAC-3-70 manufactured by Sanei Kaken Co., Ltd .: substrate (LDPE Layer (low density polyethylene resin layer)) / adhesive layer (EVA layer)) was laminated to produce a laminate composed of conductive layer / polymer piezoelectric film / protective film.

<Example 2>
The same as in Example 1 except that the protective film was changed to PAC-3-30 (film composed of a base material (PP layer (polypropylene resin layer)) / adhesive layer (EVA layer)) manufactured by Sanei Kaken Co., Ltd. Thus, a laminate composed of a conductive layer / polymer piezoelectric film / protective film was produced.

<Example 3>
Example 1 except that the protective film was changed to PAC-3-50THK (film made of base material (LDPE layer) / adhesive layer (special PO layer (special polyolefin resin layer))) manufactured by Sanei Kaken Co., Ltd. In the same manner, a laminate composed of a conductive layer / polymer piezoelectric film / protective film was produced.

<Comparative Example 1>
A laminate composed of a conductive layer / polymer piezoelectric film was produced in the same manner as in Example 1 except that the protective film was not bonded.

<Example 4: Production of a laminate having a refractive index adjusting layer>
As solid content, 58% by mass of zirconium oxide fine particles having an average particle size of 0.02 μm, 42% by mass of urethane acrylate (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Purple Light UV7600B), and a photopolymerization initiator (Ciba Specialty Chemicals Co., Ltd.) Manufactured by IRGACURE 184) was mixed with 5% by mass, and diluted with methyl ethyl ketone so that the solid content was 10% by mass, to prepare a coating solution for refractive index adjustment layer.
As the zirconium oxide fine particles, a dispersion of zirconium oxide fine particles (ZRMEK 25% -F47 manufactured by CI Kasei Co., Ltd.) was used, and the dispersion was mixed so that the solid content was the above-mentioned parts by mass.

Next, the refractive index adjusting layer coating solution is applied to one main surface (main surface on which the conductive layer is formed) of the polymer piezoelectric film prepared in Production Example 1 using a roll coater (line speed: 10 m / min). Except that the refractive index adjustment layer having a thickness of 100 nm is formed by irradiating with a metal halide lamp an ultraviolet ray with an integrated light quantity of 500 mJ / cm ² after passing through a drying oven set at 80 ° C. and drying the solvent. In the same manner as in Example 1, a laminate composed of conductive layer / refractive index adjusting layer / polymer piezoelectric film / protective film was produced.

<Example 5: Production of a laminate having a refractive index adjusting layer and an anti-block hard coat layer>
Except for forming the refractive index adjustment layer after forming the anti-block hard coat layer on both main surfaces of the polymer piezoelectric film before forming the refractive index adjustment layer by the following procedure, A laminate composed of conductive layer / refractive index adjusting layer / anti-block hard coat layer / polymer piezoelectric film / anti-block hard coat layer / protective film was prepared.

-Formation of anti-block hard coat layer-
The anti-block hard coat layer is coated on one main surface of the polymer piezoelectric film with an acrylic resin coating liquid (manufactured by Toyo Ink, anti-block hard coat LIODURAS TYAB-014) with a roll coater (line speed 10 m / min). Then, after passing through a drying furnace set at 80 ° C. to dry the solvent, the film was formed by irradiating with a metal halide lamp an ultraviolet ray with an integrated light quantity of 1000 mJ / cm ² . The thickness of the anti-block hard coat layer was 2 μm. This process was also performed on the other main surface of the polymer piezoelectric film to form an anti-block hard coat layer on the other main surface of the polymer piezoelectric film.

<Characteristic>
About the laminated body manufactured in each example, the thermal shrinkage difference after heating the laminated body (laminated body with the protective film peeled off) at 150 ° C. for 30 minutes (thermal shrinkage difference in MD direction and thermal shrinkage ratio in TD direction) Was measured according to the method described above. The results are shown in Table 2.

<Evaluation>
[Lamination evaluation]
Conductive layer side of the laminate manufactured in each example while peeling one release film of transparent double-sided adhesive tape (LUCIACS CS9661TS manufactured by Nitto Denko Corporation, composition: release film / adhesive layer (25 μm) / release film) On the other hand, using a laminator, a transparent double-sided pressure-sensitive adhesive tape from which one release film was peeled off was bonded by roll-to-roll.
Similarly, while peeling off the protective film on the side opposite to the conductive layer of the laminate produced in each example, and peeling off one release film of the transparent double-sided adhesive tape, what is the conductive layer of the laminate? A transparent double-sided pressure-sensitive adhesive tape from which one release film was peeled off was attached to the opposite surface side using a roll-to-roll using a laminator.
Thus, a laminate for evaluation of release film / adhesive layer / laminate body / adhesive layer / release film was obtained.

A visual inspection was conducted in the evaluation laminate 1m ² and the evaluation was performed according to the following criteria. The results are shown in Table 1.
A: The number of foreign matters such as dust caught between the laminate and the adhesive layer is 3 / m ² or less B: The number of foreign matters such as dust caught between the laminate and the adhesive layer is 4 / m 2 ² or more and less than 100 C: The number of foreign matters such as dust caught between the laminate and the adhesive layer is 100 / m ² or more

  From the above results, it can be seen that in this example, the laminate evaluation is better than that of the comparative example, and foreign matter such as dust is suppressed from being caught between the laminate and the adhesive layer. Thereby, it turns out that the laminated body of a present Example can suppress the final product yield fall by the inclusion of the foreign material in an intermediate process, when manufacturing a press detection apparatus and a device using the same.

10 Polymer piezoelectric film 12A Intermediate layer (functional layer)
12B Intermediate layer (functional layer)
14A electrode (conductive layer)
14B electrode (conductive layer)
16 Protective film 18A Lead electrode 18B Lead electrode 20A Adhesive layer 20B Adhesive layer 22A Release film 22B Release film 24 Base material

Claims (11)

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 conductive layer provided on one main surface of the polymer piezoelectric film;
A peelable protective film provided on the other main surface of the polymer piezoelectric film;
A laminate having   The laminate according to claim 1, wherein the conductive layer is patterned.   3. The functional layer according to claim 1, further comprising a functional layer between at least one of the polymer piezoelectric film and the protective film and between the polymer piezoelectric film and the conductive layer. Laminated body.   The laminate according to claim 3, wherein the functional layer is at least one of a refractive index adjusting layer, an easy adhesion layer, a hard coat layer, an antistatic layer, and an antiblock layer.   The thermal contraction rate when the laminated body from which the protective film has been peeled is heated at 150 ° C for 30 minutes is 2.0% or less in both the MD direction and the TD direction. Laminated body.   The said conductive layer is a transparent conductive layer, The laminated body of any one of Claims 1-5. The piezoelectric polymer film is 5% or less internal haze to visible light, and, 25 ° C. In the stress - of claims 1 to 6 piezoelectric constant d ₁₄ measured by the charge method is 1 pC / N or more The laminated body of any one of Claims. The said helical chiral polymer (A) is a polylactic acid-type polymer which has a principal chain containing the repeating unit represented by following formula (1), It is any one of Claims 1-7. Laminated body.

  The laminated body according to any one of claims 1 to 8, wherein the helical chiral polymer (A) has an optical purity of 95.00% ee or higher.   Content of the said helical chiral polymer (A) is 80 mass% or more, The laminated body of any one of Claims 1-9.   The polymer 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 laminate according to any one of claims 1 to 10, comprising 0.01 to 10 parts by mass with respect to 100 parts by mass of the molecule (A).