JP2019179877A - Piezoelectric fiber, piezoelectric fiber structure, piezoelectric fabric, piezoelectric knitted fabric, piezoelectric device, force sensor and actuator - Google Patents

Abstract

To provide a piezoelectric fiber that can produce a piezoelectric fiber structure with excellent antibacterial properties, a piezoelectric fiber structure excellent in antibacterial properties, a piezoelectric fabric, a piezoelectric knitted fabric, a piezoelectric device, a force sensor, and an actuator.SOLUTION: The piezoelectric fiber includes: a region (A) containing a helical chiral polymer (A) having optical activity; and a region (B), containing a helical chiral polymer (B), having chirality different from that of the helical chiral polymer (A), having optical activity.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a piezoelectric fiber, a piezoelectric fiber structure, a piezoelectric fabric, a piezoelectric knitted fabric, a piezoelectric device, a force sensor, and an actuator.

  In recent years, the application of piezoelectric materials containing helical chiral polymers to piezoelectric devices such as sensors and actuators has been studied. In such a piezoelectric device, a film-shaped piezoelectric body is used.

  Attention has been focused on the use of polymers having optical activity such as polypeptides and polylactic acid-based polymers as the helical chiral polymer contained in the piezoelectric body. Among these, it is known that polylactic acid polymers exhibit piezoelectricity only by mechanical stretching operation. It is known that a piezoelectric body using a polylactic acid-based polymer does not require poling treatment and the piezoelectricity does not decrease for several years.

For example, a polymeric piezoelectric material containing a polylactic acid polymer, large piezoelectric constant d ₁₄ is polymeric piezoelectric materials have been reported that excellent transparency (for example, see Patent Documents 1 and 2).
Recently, an attempt has been made to use a material having piezoelectricity by covering a conductor.
For example, a piezo cable is known that includes a center conductor, a piezoelectric material layer, an outer conductor, and a jacket that are coaxially arranged in order from the center to the outside (see, for example, Patent Document 3).
Also known is a piezoelectric element obtained by coating a conductive fiber with a fiber made of a piezoelectric polymer containing polyvinylidene fluoride or polylactic acid (for example, see Patent Document 4).
Furthermore, a piezoelectric antibacterial fabric having a piezoelectric property and antibacterial properties by winding a piezoelectric L-type polylactic acid (PLLA) yarn, a slit ribbon or the like around a center yarn is known (for example, non-patented) Reference 1).

Japanese Patent No. 4934235 International Publication No. 2010/104196 JP-A-10-132669 International Publication No. 2014/058077

34th Ferroelectric Application Conference (2017), 03-M-03 “Piezoelectric antibacterial fabric using polylactic acid fiber”

  By the way, when the film-shaped polymeric piezoelectric material described in Patent Document 1 and Patent Document 2 is used as a piezoelectric body in a place with a large unevenness, a place with a large amount of deformation, etc. (for example, as part or all of a wearable product) When used), deformation may cause breakage in the piezoelectric body, resulting in damage such as wrinkles. As a result, the piezoelectric sensitivity of the piezoelectric body (for example, the sensor sensitivity when the piezoelectric body is used as a sensor and the operation sensitivity when the piezoelectric body is used as an actuator may be mentioned; the same applies hereinafter) may be reduced. .

  Further, Non-Patent Document 1 describes a piezoelectric fiber structure having antibacterial properties, but a piezoelectric fiber structure excellent in antibacterial properties is required in a configuration other than Non-Patent Document 1.

  Accordingly, the present invention provides a piezoelectric fiber capable of producing a piezoelectric fiber structure excellent in antibacterial properties, and a piezoelectric fiber structure, piezoelectric fabric, piezoelectric knitted fabric, piezoelectric device, force sensor, and actuator excellent in antibacterial properties. With the goal.

Specific means for achieving the above object are as follows.
<1> Region (A) containing a helical chiral polymer (A) having optical activity, and a region containing a helical chiral polymer (B) having optical activity and different in chirality from the helical chiral polymer (A) ( A piezoelectric fiber having a region (B) including B).
<2> The piezoelectric fiber according to <1>, wherein the region (A) and the region (B) are located along the length direction of the piezoelectric fiber.
<3> The piezoelectric fiber according to <1> or <2>, which is a hollow fiber, and wherein the region (A) and the region (B) constitute a cylindrical portion of the hollow fiber.
<4> The helical chiral polymer (A) and the helical chiral polymer (B) are polylactic acid polymers having a main chain containing a repeating unit represented by the following formula (1) <1> to <3> The piezoelectric fiber according to any one of the above.

<5> The helical chiral polymer (A) contains more than 50 mol% of L-form components as structural units, and the helical chiral polymer (B) contains more than 50 mol% of D-form components as structural units <1 > To <4> The piezoelectric fiber according to any one of the above.
<6> The helical chiral polymer (A) contains 90 mol% or more of L-form components as structural units, and the helical chiral polymer (B) contains 90 mol% or more of D-form components as structural units <1 The piezoelectric fiber according to any one of> to <5>.

<7> A piezoelectric fiber structure in which the piezoelectric fiber according to any one of <1> to <6> is spirally wound.
<8> The piezoelectric fiber structure according to <7>, wherein the region (A) and the region (B) are wound at an angle of 15 ° to 75 ° with respect to the helical axis.
<9> The piezoelectric fiber structure according to <8>, in which the region (A) and the region (B) that are wound in a spiral are adjacent to each other.

<10> A piezoelectric fabric comprising a fabric structure composed of warp and weft, wherein at least one of the warp and weft includes the piezoelectric fiber structure according to any one of <7> to <9>.

<11> A piezoelectric knitted fabric comprising a knitted fabric structure including the piezoelectric fiber structure according to any one of <7> to <9>.

<12> A piezoelectric device comprising the piezoelectric fabric according to <10> or the piezoelectric knitted fabric according to <11>.

<13> A force sensor including the piezoelectric fiber structure according to any one of <7> to <9>.

<14> An actuator comprising the piezoelectric fiber structure according to any one of <7> to <9>.

  According to the present invention, there are provided a piezoelectric fiber capable of producing a piezoelectric fiber structure excellent in antibacterial property, and a piezoelectric fiber structure, piezoelectric fabric, piezoelectric knitted fabric, piezoelectric device, force sensor and actuator excellent in antibacterial property. Can do.

It is a front view which shows the specific aspect of the piezoelectric fiber of this indication. It is a side view which shows the specific aspect 1 of the piezoelectric fiber structure of this indication. It is a side view which shows the specific aspect 2 of the piezoelectric fiber structure of this indication. It is the schematic which shows the specific aspect of the piezoelectric knitted fabric of this indication. 1 is a schematic view showing a 2C-shaped spinneret used in Example 1. FIG.

Hereinafter, embodiments of the present disclosure will be described.
In the present disclosure, numerical ranges indicated using “to” indicate ranges including numerical values described before and after “to” as the minimum value and the maximum value, respectively. In a numerical range described in stages in the present disclosure, an upper limit value or a lower limit value described in a numerical range may be replaced with an upper limit value or a lower limit value in another numerical range. Further, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the values shown in the examples.
Further, in the present disclosure, the “film” is a concept including not only what is generally called “film” but also what is generally called “sheet”.

[Piezoelectric fiber]
The piezoelectric fiber of the present disclosure includes a region (A) containing a helical chiral polymer (A) having optical activity, and a helical chiral polymer (B) having optical activity that is different in chirality from the helical chiral polymer (A). And a region (B) including By using this piezoelectric fiber, a piezoelectric fiber structure excellent in antibacterial properties can be produced as described later.

  In the piezoelectric fiber of the present disclosure, the region (A) and the region (B) are preferably located along the length direction of the piezoelectric fiber. Moreover, it is preferable that a piezoelectric fiber is a fiber which consists of an area | region (A) and an area | region (B).

  The piezoelectric fiber of the present disclosure is a hollow fiber, and it is preferable that the region (A) and the region (B) constitute a hollow fiber cylindrical portion. For example, by extruding a resin material containing the helical chiral polymer (A) to be the region (A) and a resin material containing the helical chiral polymer (B) to be the region (B) from the 2C-shaped spinneret, In the direction, a hollow fiber is obtained comprising a region (A) constituting half of the hollow cylindrical shape and a region (B) constituting the remaining half of the hollow cylindrical shape. When the piezoelectric fiber is a hollow fiber, it tends to be excellent in flexibility and flexibility (flexibility).

(Specific embodiment of piezoelectric fiber)
Hereinafter, an example of a specific aspect of the piezoelectric fiber will be described with reference to FIG.
As shown in FIG. 1, the piezoelectric fiber 100 is a hollow fiber having a hollow portion 3, and in the length direction, the region (A) 1 and the region (B) 2 constitute a hollow fiber cylindrical portion. By winding such a piezoelectric fiber 100 in a spiral shape, a piezoelectric fiber structure as shown in FIGS. 2 and 3 can be obtained.

(Helical Chiral Polymer (A) and Helical Chiral Polymer (B))
The region (A) includes the helical chiral polymer (A) having optical activity, and the region (B) includes the helical chiral polymer (B) having chirality different from that of the helical chiral polymer (A).
Here, the “helical chiral polymer having optical activity” refers to a polymer having a helical structure and a molecular optical activity.

Examples of the helical chiral polymer (A) and the helical chiral polymer (B) (hereinafter also referred to as “helical chiral polymer”) 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.

  From the viewpoint of improving the piezoelectricity of the piezoelectric fiber, the helical chiral polymer (A) and the helical chiral polymer (B) preferably have an optical purity of 95.00% ee or more, and 96.00% ee or more. More preferably, it is more preferably 99.00% ee or more, and even more preferably 99.99% ee or more. Desirably, it is 100.00% ee. By setting the optical purity of the helical chiral polymer (A) and the helical chiral polymer (B) within the above range, the packing property of the polymer crystal expressing the piezoelectricity is enhanced, and as a result, the piezoelectricity of the piezoelectric fiber is improved. It is considered to be high.

Here, the optical purity of the helical chiral polymer 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 is
“The amount difference (absolute value) between the amount of L-form [mass%] of the helical chiral polymer and the amount of D-form [mass%] of the helical chiral polymer” is “the amount of L-form of the helical chiral polymer [ It is a value obtained by multiplying (multiplying) "numerical value" divided by "total amount of D-form [mass%] of helical chiral polymer" by "100".

  In addition, the value obtained by the method using a high performance liquid chromatography (HPLC) is used for the quantity [mass%] of the L form of a helical chiral polymer, and the quantity [mass%] of the D form of a helical chiral polymer. Details of the specific measurement will be described later.

  The helical chiral polymer (A) preferably contains more than 50 mol% of the L-form component as a structural unit, more preferably contains 70 mol% or more, more preferably contains 80 mol% or more, and more preferably contains 90 mol% or more. It is particularly preferred. The upper limit of the content of the L-form component in the helical chiral polymer (A) is not particularly limited, and may be 100 mol% or less, or 99 mol% or less.

  The helical chiral polymer (B) preferably contains more than 50 mol% of the D-form component as a structural unit, more preferably contains 70 mol% or more, more preferably contains 80 mol% or more, and more preferably contains 90 mol% or more. It is particularly preferred. The upper limit of the content of the D-form component in the helical chiral polymer (B) is not particularly limited, and may be 100 mol% or less, or 99 mol% or less.

  As the helical chiral polymer (A) and the helical chiral polymer (B), from the viewpoint of increasing the optical purity and improving the piezoelectricity, a polymer having a main chain containing a repeating unit represented by the following formula (1): Lactic acid polymers are preferred.

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 -Copolymer of lactic acid or a compound copolymerizable with D-lactic acid "or a mixture of both.
The helical chiral polymer (A) and the helical chiral polymer (B) are preferably polylactic acid among polylactic acid polymers. The helical chiral polymer (A) is more preferably a homopolymer of L-lactic acid (PLLA, also simply referred to as “L-form”), and the helical chiral polymer (B) is a homopolymer of D-lactic acid (PDLA, More simply, also referred to as “D-form”).

Polylactic acid is a polymer in which lactic acid is polymerized by an ester bond.
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.

When the helical chiral polymer (A) contains L-lactic acid and D-lactic acid as structural units, the content of L-lactic acid is preferably higher than the content of D-lactic acid.
Moreover, when helical chiral polymer (B) contains L-lactic acid and D-lactic acid as a structural unit, it is preferable that the content rate of D-lactic acid is higher than the content rate of L-lactic acid.

  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, mandelic acid; cyclic esters such as glycolide, β-methyl-δ-valerolactone, γ-valerolactone, 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, and the concentration of the structure derived from the copolymer component in the helical chiral polymer (B) is 20 mol. % Or less is preferable.
For example, when the helical chiral polymer (A) and the helical chiral polymer (B) are polylactic acid polymers, the structure derived from lactic acid in the polylactic acid polymer and a compound copolymerizable with lactic acid The concentration of the structure derived from the copolymer component is preferably 20 mol% or less with respect to the total number of moles of the structure derived from (copolymer component).

  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) and the helical chiral polymer (B) is preferably 50,000 to 1,000,000.
When the helical chiral polymer has an Mw of 50,000 or more, the mechanical strength of the piezoelectric fiber is improved. The Mw is preferably 100,000 or more, and more preferably 200,000 or more.
On the other hand, when the helical chiral polymer has Mw of 1 million or less, the moldability when obtaining a piezoelectric fiber by molding (for example, extrusion molding, melt spinning) 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) and the helical chiral polymer (B) is preferably 1.1 to 5 from the viewpoint of the strength of the piezoelectric fiber, and 1.2 to 4 is more 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 point out the value measured using the gel permeation chromatograph (GPC). Here, Mn is the number average molecular weight of the helical chiral polymer.
Hereinafter, an example of a method for measuring Mw and Mw / Mn of a helical chiral polymer by GPC will be described.

-GPC measuring device-
Waters GPC-100
-Column-
Made by Showa Denko KK, Shodex LF-804
-Sample preparation-
A site corresponding to the region (A) or the region (B) 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 are calculated.

Commercially available polylactic acid can be used as the polylactic acid polymer that is an example of the helical chiral polymer.
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 a polylactic acid polymer is used as the helical chiral polymer, in order to increase the weight average molecular weight (Mw) of the polylactic acid polymer to 50,000 or more, the polylactic acid polymer is obtained by the lactide method or the direct polymerization method. It is preferable to manufacture.

Each of the region (A) and the region (B) may contain only one kind or two or more kinds of the above-described helical chiral polymer (A) and helical chiral polymer (B). Good.
The content of the helical chiral polymer (A) contained in the region (A) (the total content in the case of 2 or more) is preferably 80% by mass or more based on the total amount of the region (A).
The content of the helical chiral polymer (B) contained in the region (B) (total content in the case of 2 or more) is preferably 80% by mass or more based on the total amount of the region (B).

(Stabilizer)
At least one of the region (A) and the region (B) further has a weight average molecular weight of 200 to 1 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. 60000 stabilizers (C) may be contained. Thereby, the heat-and-moisture resistance of a piezoelectric fiber can be improved more.

  As the stabilizer (C), for example, “stabilizer (B)” described in paragraphs 0039 to 0055 of International Publication No. 2013/054918 can be used.

Examples of the compound containing a carbodiimide group (carbodiimide compound) that can be used as the stabilizer (C) 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, for example, the method described in JP2011-256337A.
As the carbodiimide compound, a commercially available product may be used. For example, B2756 (trade name) manufactured by Tokyo Chemical Industry Co., Ltd., Carbodilite (registered trademark) LA-1 (trade name) manufactured by Nisshinbo Chemical Co., Ltd., Stabaxol P , Stabaxol P400, Stabaxol I (both are trade names) and the like.

  Examples of the compound (isocyanate compound) containing an isocyanate group in one molecule that can be used as the stabilizer (C) 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. Is mentioned.

  As a compound (epoxy compound) containing an epoxy group in one molecule that can be used as the stabilizer (C), 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 (C) 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 (C) is more easily moved, and the effect of improving the heat and moisture resistance is more effectively exhibited.
The weight average molecular weight of the stabilizer (C) 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 at least one of the region (A) and the region (B) contains the stabilizer (C), at least one of the region (A) and the region (B) contains only one kind of the stabilizer (C). It may also be contained in two or more.
When at least one of the region (A) and the region (B) contains the stabilizer (C), the content of the stabilizer (C) is 0.01 parts by mass to 100 parts by mass of the helical chiral polymer. It is preferably 10 parts by mass, more preferably 0.01 parts by mass to 5 parts by mass, still more preferably 0.1 parts by mass to 3 parts by mass, and 0.5 parts by mass to 2 parts by mass. It is particularly preferred that
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 (C) 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. (C1) 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 ( And an embodiment in which C2) is used in combination. The weight average molecular weight of the stabilizer (C1) 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 (C1) are almost the same value. .
When the stabilizer (C1) and the stabilizer (C2) are used in combination as the stabilizer (C), it is preferable that a large amount of the stabilizer (C1) is contained from the viewpoint of improving the transparency.
Specifically, the stabilizer (C2) is preferably in the range of 10 parts by weight to 150 parts by weight with respect to 100 parts by weight of the stabilizer (C1) 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 C-1 to C-3) of the stabilizer (C) are shown. In the stabilizers C-1 and C-3, i-Pr represents an isopropyl group.

Hereinafter, with respect to the stabilizers C-1 to C-3, compound names, commercial products, and the like are shown.
Stabilizer C-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 C-2 The compound name is poly (4,4′-dicyclohexylmethanecarbodiimide). As a commercially available product, “Carbodilite (registered trademark) LA-1” manufactured by Nisshinbo Chemical Co., Ltd. can be cited as having a weight average molecular weight of about 2000.
Stabilizer C-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 piezoelectric fiber 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 (C) 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.

  Furthermore, the piezoelectric fiber of the present disclosure is preferably drawn from the viewpoint of enhancing piezoelectricity, and more preferably drawn mainly in a uniaxial direction. By stretching mainly in a uniaxial direction, the molecular chains of the helical chiral polymer (A) contained in the region (A) and the helical chiral polymer (B) contained in the region (B) are oriented in one direction, and It can be aligned with high density. Thereby, higher piezoelectricity can be obtained.

  When the piezoelectric fiber is stretched mainly in a uniaxial direction, the stretching ratio of the main stretching is preferably 2 to 8 times, more preferably 3 to 5 times, still more preferably 3 to 4 times, and secondary stretching. The stretching ratio (stretching in the direction intersecting with the main stretching direction, which is smaller than the main stretching) is preferably 1 to 3 times, more preferably 1.1 to 2.5 times, and 1.2 A ratio of 2 to 2.0 is more preferable.

(Orientation degree F)
In at least one of the region (A) and the region (B), the orientation degree F obtained by the following formula (a) is preferably in the range of 0.5 or more and less than 1.0.
Orientation degree F = (180 ° −α) / 180 ° (a)
However, (alpha) represents the half value width of the peak derived from an orientation. The unit of α is °.
The degree of orientation F is more preferably 0.7 or more and less than 1.0, and still more preferably 0.8 or more and less than 1.0.
If the degree of orientation F is 0.5 or more, there are many helical chiral 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, resulting in higher piezoelectricity. It becomes possible to express sex.
If the orientation degree F is less than 1.0, the longitudinal crack strength is improved.

  The degree of orientation F is an index indicating the degree of orientation of the helical chiral polymer contained in the piezoelectric fiber. The degree of orientation F is, for example, a c-axis orientation measured by a wide-angle X-ray diffractometer (RINT2550, manufactured by Rigaku Corporation, attached device: rotating sample stage, X-ray source: CuKα, output: 40 kV 370 mA, detector: scintillation counter). Degree. For example, a piezoelectric fiber as a sample is fixed to a holder of a wide-angle X-ray diffractometer, the azimuth distribution intensity of the crystal plane peak [(110) plane / (200) plane] is measured, and the obtained azimuth distribution curve ( In the X-ray interference diagram), the orientation degree F (degree of C-axis orientation) may be calculated from the above formula from the crystallinity and the half width (α) of the peak.

(Crystallinity)
In at least one of the region (A) and the region (B), the crystallinity is preferably 20% to 80%, more preferably 25% to 70%, and further preferably 30% to 60%. .
When the crystallinity is 20% or more, the piezoelectricity of the piezoelectric fiber is maintained high. When the crystallinity is 80% or less, the transparency of the piezoelectric fiber is maintained high.
When the degree of crystallinity is 80% or less, for example, when the piezoelectric fiber is manufactured by stretching, whitening, breakage, and the like hardly occur, and thus the piezoelectric fiber is easy to manufacture. Further, when the degree of crystallinity is 80% or less, for example, when a raw material of piezoelectric fiber (for example, polylactic acid) is produced by drawing after melt spinning, it becomes a fiber having high flexibility and supple properties, and the piezoelectric fiber Easy to manufacture.

-Specific examples of piezoelectric fiber-
Specific examples of the piezoelectric fiber include monofilament yarn, multifilament yarn, spun yarn, and the like.

-Monofilament yarn The monofilament yarn has a single yarn fineness of preferably 3 dtex to 30 dtex, more preferably 5 dtex to 20 dtex.
When the single yarn fineness is 3 dtex or more, it is easy to handle the yarn in the fabric preparation process, the weaving process and the like. On the other hand, when the single yarn fineness is 30 dtex or less, fusion between yarns hardly occurs.
The monofilament yarn is preferably obtained by directly spinning and drawing in consideration of cost. The monofilament yarn may be obtained.

-Multifilament yarn The total fineness of the multifilament yarn is preferably 30 dtex to 600 dtex, more preferably 100 dtex to 400 dtex.
As the multifilament yarn, for example, any one-step yarn such as a spin draw yarn or two-step yarn obtained by drawing UDY (undrawn yarn), POY (highly oriented undrawn yarn) or the like can be used. . Multifilament yarns may be obtained.
Commercially available products of polylactic acid monofilament yarn and polylactic acid multifilament yarn include Toray's Ecodia (registered trademark) PLA, Unitika's Terramac (registered trademark), and Kuraray's Plastarch (registered trademark) It is.

[Method of manufacturing piezoelectric fiber]
There is no particular limitation on the method of manufacturing the piezoelectric fiber. For example, a resin material containing the helical chiral polymer (A) to be the region (A) and a resin material containing the helical chiral polymer (B) to be the region (B) are prepared, and the helical chiral polymer (A) is prepared. Piezoelectric fibers can be obtained by melting the resin material containing the resin material and the helical chiral polymer (B), extruding each from a spinneret of 2C shape, etc., and drawing the extruded composite fiber (melting) Spinning drawing method).
In addition, after spinning, it is preferable to maintain the atmospheric temperature in the vicinity of the yarn until cooling and solidification within a certain temperature range.
Moreover, you may give an oil agent as a finishing agent after spinning, extending | stretching, and after the winding mentioned later as needed.
The filament yarn as the piezoelectric fiber may be obtained, for example, by further dividing the filament yarn obtained by the melt spinning drawing method.

-Cross-sectional shape As the cross-sectional shape of the piezoelectric fiber, in the cross-section in the direction perpendicular to the longitudinal direction of the piezoelectric fiber, hollow shape, circular shape, elliptical shape, rectangular shape, collar shape, ribbon shape, four-leaf shape, star shape, Various cross-sectional shapes such as irregular shapes can be applied. Moreover, it is preferable that a part is a region (A) and the rest is a region (B) along the longitudinal direction of the piezoelectric fiber, and a cross section (preferably a direction perpendicular to the longitudinal direction of the piezoelectric fiber). It is preferable that the arbitrary cross section of (A) includes the region (A) and the region (B).

[Piezoelectric fiber structure]
The piezoelectric fiber structure of the present disclosure is formed by spirally winding the above-described piezoelectric fiber. The piezoelectric fiber structure of the present disclosure is excellent in antibacterial properties. The effect is estimated as follows. When tension is applied to the piezoelectric fiber structure of the present disclosure, the region (A) is charged, and the region (B) is charged to a potential opposite to that of the region (A), so that the region (A) and the region (B) are charged. A strong electric field is generated at the interface. And when bacteria etc. exist in this generated strong electric field, since the cell membrane of bacteria etc. is destroyed by a strong electric field, the piezoelectric fiber structure of this indication has an antibacterial action.

The region (A) and the region (B) are angles of 15 ° to 75 ° (45 ° ± 30 °) with respect to the helical axis (spiral angle) from the viewpoint of improving the piezoelectric sensitivity and the stability of the piezoelectric output. ), Preferably at an angle of 25 ° to 65 ° (45 ° ± 20 °), more preferably at an angle of 35 ° to 65 ° (45 ° ± 10 °) More preferably, the wire is wound around.
The “spiral axis” means the central axis of the spiral structure formed by the region (A) and the region (B) when the region (A) and the region (B) are spirally wound.
The piezoelectric fiber structure of the present disclosure may be manufactured by, for example, winding the above-described piezoelectric fiber by twisting, crimping, or the like.
It is preferable that the spiral angle of the region (A) and the spiral angle of the region (B) are substantially the same, for example, the difference between the spiral angles is within ± 5 °.

  The piezoelectric fiber structure of the present disclosure may further include a long core material, and the piezoelectric fiber may be spirally wound around the long core material. Examples of the long core material include a non-conductive core material and a conductor.

The material of the non-conductive core material is not particularly limited as long as the material does not have conductivity. For example, polyamide resin, polyester resin, acrylic resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polysulfone resin And polymer resins such as polyether resins and polyurethane resins; cellulosic resins; and inorganic materials such as glass, silica gel, and ceramics. These materials may be used alone or in combination of two or more.
The shape (long shape) of the non-conductive core material and the major axis diameter are not particularly limited, but the non-conductive core material may be a core material having a fiber shape composed of one or a plurality of bundles. preferable.
Examples of the core material having a fiber shape include yarn (monofilament yarn, multifilament yarn).

  The conductor is preferably a good electrical conductor, for example, copper wire, aluminum wire, SUS wire, metal wire coated with insulating film, carbon fiber, resin fiber integrated with carbon fiber, tinsel wire, organic conductive Materials and the like. Kinshi wire refers to a fiber in which copper foil is wound in a spiral. Of the conductors, tinsel wire and carbon fiber are preferable from the viewpoint of improving piezoelectric sensitivity and stability of piezoelectric output and imparting high flexibility.

  The piezoelectric fiber structure of the present disclosure may not include a long core material. When the piezoelectric fiber structure does not have a long core material, it tends to be excellent in flexibility and flexibility (flexibility), and the step of preparing a long core material is omitted. The manufacturing process of the piezoelectric fiber structure is simplified.

(Specific embodiment 1 of piezoelectric fiber structure)
Hereinafter, specific embodiment 1 will be described as an example of the piezoelectric fiber structure with reference to FIG.
As shown in FIG. 2, the piezoelectric fiber structure 10 according to a specific embodiment is formed by winding a piezoelectric fiber in a spiral shape. The piezoelectric fiber region (A) 1 is wound from one end to the other end at a spiral angle α1 with respect to the spiral axis G, and the piezoelectric fiber region (B) 2 is wound with respect to the spiral axis G. The spiral angle α2 is wound from one end to the other end so that there is no gap between the adjacent region (A) 1 and the region (B) 2, that is, the adjacent region (A) 1 and the region (B) The region (A) 1 and the region (B) 2 are spirally wound in the same direction so as to be in contact with 2.
In FIG. 2, when viewed from one end of the central axis (spiral axis) G (right end side in the case of FIG. 2), the region (A) 1 and the region (B) 2 are left-handed from the front side toward the back side ( An example of S winding wound counterclockwise) is shown.
Further, in FIG. 2, the main orientation direction of the helical chiral polymer (A) contained in the region (A) 1 is indicated by a double-pointed arrow E1, and the helical chiral polymer (B ) Is indicated by a double arrow E2. That is, the main orientation direction of the helical chiral polymer (A) and the arrangement direction of the region (A) 1 (the length direction of the region (A) 1) are substantially parallel, and the helical chiral polymer (B ) And the arrangement direction of the region (B) 2 (the length direction of the region (B) 2) are substantially parallel to each other.
Furthermore, in FIG. 2, the main orientation direction of the helical chiral polymer (A) contained in the region (A) 1 is substantially parallel to the main orientation direction of the helical chiral polymer (B) contained in the region (B) 2. It has become.

(Specific embodiment 2 of piezoelectric fiber structure)
Next, specific embodiment 2 will be described as an example of the piezoelectric fiber structure with reference to FIG.
As shown in FIG. 3, the piezoelectric fiber structure 20 of a specific embodiment is formed by spirally winding a piezoelectric fiber. The piezoelectric fiber region (A) 1 is wound from one end to the other end at a spiral angle α1 with respect to the spiral axis G, and the piezoelectric fiber region (B) 2 is wound with respect to the spiral axis G. The spiral angle α2 is wound from one end to the other end so that there is no gap between the adjacent region (A) 1 and the region (B) 2, that is, the adjacent region (A) 1 and the region (B) The region (A) 1 and the region (B) 2 are spirally wound in the same direction so as to be in contact with 2.
In FIG. 3, when viewed from one end of the central axis (spiral axis) G (right end side in the case of FIG. 3), the region (A) 1 and the region (B) 2 are clockwise when viewed from the near side to the far side. The example of Z winding wound by (clockwise) is shown.
In FIG. 3, the main orientation direction of the helical chiral polymer (A) contained in the region (A) 1 is indicated by a double arrow E3, and the helical chiral polymer (B ) Is indicated by a double arrow E4. That is, the main orientation direction of the helical chiral polymer (A) and the arrangement direction of the region (A) 1 (the length direction of the region (A) 1) are substantially parallel, and the helical chiral polymer (B ) And the arrangement direction of the region (B) 2 (the length direction of the region (B) 2) are substantially parallel to each other.
Further, in FIG. 3, the main orientation direction of the helical chiral polymer (A) contained in the region (A) 1 is substantially parallel to the main orientation direction of the helical chiral polymer (B) contained in the region (B) 2. It has become.

<Fiber>
The piezoelectric fiber structure may include fibers other than piezoelectric fibers (hereinafter also simply referred to as “fibers”).
The fiber is preferably wound in a direction different from the winding direction of the piezoelectric fiber, and preferably has a braided structure in which the piezoelectric fiber and the fiber are alternately crossed.
The fiber winding direction (right-handed or left-handed) may be the same direction as the piezoelectric fiber winding direction or a different direction.

The fiber is not particularly limited. For example, polymer fibers such as aramid fiber, polyester fiber, acrylic fiber, polyethylene fiber, polypropylene fiber, vinyl chloride fiber, polysulfone fiber, polyether fiber, polyurethane fiber; cotton, hemp, silk And natural fibers such as cellulose; semi-synthetic fibers such as acetate; regenerated fibers such as rayon and cupra; and glass fibers.
These fibers may be used alone or in combination of two or more.
Examples of the fiber include monofilament yarn and multifilament yarn. Examples of the single yarn fineness of the monofilament yarn include the same range as the single yarn fineness of the monofilament yarn in the piezoelectric fiber described above. Examples of the total fineness of the multifilament yarn include a range similar to the total fineness of the multifilament yarn in the piezoelectric fiber described above.

[Method for producing piezoelectric fiber structure]
The manufacturing method of the piezoelectric fiber structure of the present disclosure is a manufacturing method of the piezoelectric fiber structure for manufacturing the above-described piezoelectric fiber structure, the step of preparing the above-described piezoelectric fiber, and winding the prepared piezoelectric fiber And a step of performing.
The piezoelectric fiber structure may be manufactured by winding the piezoelectric fiber by twisting, crimping, or the like.

  In the step of preparing the piezoelectric fiber, for example, a resin material containing the helical chiral polymer (A) and a resin material containing the helical chiral polymer (B) are melted, extruded from a spinneret of 2C shape, etc., and extruded to manufacture. A piezoelectric fiber may be manufactured by stretching the composite fiber.

  In the step of winding the piezoelectric fiber, the piezoelectric fiber may be twisted by a swirl flow and wound spirally. Using a device that generates a swirling flow, for example, a device including a compressor and a cyclone, air is blown into the cyclone using the compressor to form a swirling flow, and the piezoelectric fiber supplied into the cyclone by the swirling flow What is necessary is just to twist and to make it wind spirally.

[Piezoelectric fabric]
The piezoelectric fabric of the present disclosure includes a fabric structure composed of warp and weft, and at least one of the warp and the weft includes the above-described piezoelectric fiber structure.
Therefore, according to the piezoelectric fabric of the present disclosure, the antibacterial property is excellent similarly to the piezoelectric fiber structure of the present disclosure.
Here, the woven fabric refers to all fabric finished by forming a woven fabric structure by interlacing yarns. The piezoelectric fabric refers to a fabric that exhibits a piezoelectric effect by an external stimulus (for example, physical force) among the fabrics.

There is no restriction | limiting in particular in the textile structure in the piezoelectric fabric of this indication.
Examples of the woven structure include basic structures such as plain weave, twill weave, satin weave and the like.
The piezoelectric fiber structure of the present disclosure may be used as a warp or a weft in the piezoelectric fabric, may be used as a part of the warp, or may be used as a part of the weft.

  In the piezoelectric fabric of the present disclosure, both the warp and the weft may include the above-described piezoelectric fiber structure.

Examples of the yarn other than the piezoelectric fiber structure include a yarn containing a polymer.
Examples of the polymer in the yarn containing the polymer include general polymers such as polyester and polyolefin, and the above-described helical chiral polymer.

The piezoelectric fabric of the present disclosure may be a fabric having a three-dimensional structure. A fabric having a three-dimensional structure is a fabric that is three-dimensionally finished by knitting yarn (warp yarn, weft yarn) in the thickness direction of the fabric in addition to the two-dimensional structure.
An example of a woven fabric having a three-dimensional structure is described in, for example, JP-T-2001-513855.
In the piezoelectric fabric of the present disclosure, it is only necessary that at least a part of the yarns constituting the fabric structure is configured of the piezoelectric fiber structure of the present disclosure.

[Piezoelectric knitting]
The piezoelectric knitted fabric of the present disclosure includes a knitted fabric structure including the piezoelectric fiber structure described above.
Therefore, according to the piezoelectric knitted fabric of the present disclosure, the antibacterial property is excellent as in the piezoelectric fiber structure of the present disclosure.
Here, the knitted fabric refers to all items manufactured by knitting while forming a loop with yarn. The piezoelectric knitted fabric refers to a knitted fabric that exhibits a piezoelectric effect by an external stimulus (for example, physical force).

Examples of the yarn other than the piezoelectric fiber structure include a yarn containing a polymer.
Examples of the polymer in the yarn containing the polymer include general polymers such as polyester and polyolefin, and the above-described helical chiral polymer.

There is no restriction | limiting in particular in the knitted structure in the piezoelectric knitted fabric of this indication.
Examples of the knitted structure include basic structures such as weft knitting (horizontal knitting) and warp knitting (vertical knitting). Examples of weft knitting include flat knitting, rib knitting, double-sided knitting, pearl knitting, and circular knitting. Examples of warp knitting include basic structures such as tricot knitting, atlas knitting, diamond knitting, and Milanese knitting.
The piezoelectric fiber structure of the present disclosure may be used as a yarn in the piezoelectric knitted fabric, or may be used as a part of the yarn.

The piezoelectric knitted fabric of the present disclosure may be a knitted fabric having a three-dimensional structure. A knitted fabric having a three-dimensional structure is a knitted fabric that is three-dimensionally finished by knitting yarn in the thickness direction of the knitted fabric in addition to the two-dimensional structure.
In the piezoelectric knitted fabric of the present disclosure, it is only necessary that at least a part of the yarn constituting the knitted fabric structure is configured by the piezoelectric fiber structure of the present disclosure.

(Specific embodiment of piezoelectric knitted fabric)
Hereinafter, a specific aspect of the piezoelectric knitted fabric of the present disclosure will be described with reference to FIG.
As shown in FIG. 4, the piezoelectric knitted fabric 30 of the present disclosure has the piezoelectric fiber structure 10 and the insulating yarn 16 knitted by weft knitting, and a part of the knitted structure is shown in FIG. A piezoelectric fiber structure 10 is used.

<Use of piezoelectric fabric or piezoelectric knitted fabric>
The piezoelectric woven fabric or piezoelectric knitted fabric of the present disclosure can be applied to any application that requires piezoelectricity and antibacterial properties at least partially.

Specific examples of applications of the piezoelectric fabric or knitted fabric of the present disclosure include various clothing (shirts, suits, blazers, blouses, coats, jackets, blousons, jumpers, vests, dresses, trousers, skirts, pants, underwear (slip, petticoats) , Camisole, bra), socks, gloves, Japanese clothes, obi, kin, cold clothing, tie, handkerchief, scarf, scarf, stall, eye mask), tablecloth, footwear (sneakers, boots, sandals, pumps, mules, slippers) , Ballet shoes, kung fu shoes), towels, bags, bags (tote bags, shoulder bags, handbags, pochettes, shopping bags, eco bags, rucksacks, day packs, sports bags, Boston bags, waist bags, waist bags , Second bag, clutch bag, vanity, accessory pouch, mother bag, party bag, kimono bag), pouch case (makeup pouch, tissue case, glasses case, pen case, book cover, game pouch, key case, pass case) ), Wallet, hat (hat, cap, casket, hunting cap, ten gallon hat, tulip hat, sun visor, beret), helmet, hood, belt, apron, ribbon, corsage, brooch, curtain, wall cloth, seat cover, Sheets, futons, duvet covers, blankets, pillows, pillow covers, sofas, beds, baskets, various wrapping materials, upholstery, automotive supplies, artificial flowers, masks, bandages, ropes, various nets, fish nets, cement reinforcements, screen printing For mesh, various Ter (for the automotive, consumer electronics), various types of mesh, bedsheets (agricultural, leisure seat), civil engineering work for the textile, construction work for the textile, filter cloth, and the like.
In addition, the whole of the above specific example may be configured by the piezoelectric fabric or piezoelectric knitted fabric of the present disclosure, or only a portion requiring piezoelectricity and antibacterial properties may be configured by the piezoelectric fabric or piezoelectric knitted fabric of the present disclosure.
As the application of the piezoelectric fabric or piezoelectric knitted fabric of the present disclosure, a wearable product worn on the body is particularly suitable.

  In addition, the detail about the specific aspect of the piezoelectric knitted fabric of this indication is mentioned later with the specific aspect of a piezoelectric device.

[Piezoelectric device]
The piezoelectric device of the present disclosure includes the piezoelectric fabric of the present disclosure or the piezoelectric knitted fabric of the present disclosure.
It is preferable that an electrode is disposed on the piezoelectric fabric or the piezoelectric knitted fabric. The electrode is an electrode for detecting charges generated from the piezoelectric fiber structure.
Although there is no limitation in particular as an electrode material, Metals (Al etc.) are mentioned, However, For example, Ag, Au, Cu, Ag-Pd alloy, Ag paste, Cu paste, carbon black, ITO (crystallization) ITO and amorphous ITO), ZnO, IGZO, IZO (registered trademark), conductive polymers (polythiophene, PEDOT), Ag nanowires, carbon nanotubes, graphene, and the like.
Note that the piezoelectric device of the present disclosure preferably includes an insulator between the electrode and the woven structure or the knitted structure.
Thereby, it becomes a structure which is easy to suppress generation | occurrence | production of the electrical short circuit between electrodes.

<Use of piezoelectric fiber structure>
The piezoelectric fiber structure of the present disclosure is preferably used for applications that require antibacterial properties. Also,
For example, sensor applications (force sensors such as seating sensors, ultrasonic sensors, rackets, golf clubs, acceleration sensors and impact sensors when striking various sports equipment for ball games such as bats), actuator applications (sheet transport devices, etc.) , Energy harvesting applications (power generation wear, power generation shoes, etc.), healthcare related applications (various clothing such as T-shirts, sportswear, spats, socks, supporters, casts, diapers, shoes, insoles, watches, etc. It can be used as a wearable motion sensor provided with a sensor.
For example, the above-described piezoelectric fabric, piezoelectric knitted fabric, and piezoelectric device can be applied to these applications.

  As a method for detecting the charge or surface potential generated by the stress, strain, etc. of the piezoelectric fiber structure of the present disclosure, a method using a known non-contact type surface potential meter; an electrode made of a known conductive material is connected to the piezoelectric fiber structure For example, a method in which the piezoelectric fiber structure is electrostatically coupled to the piezoelectric fiber structure and the potential change of the electrode is read with a voltmeter in this state. Moreover, a well-known extraction electrode can be joined as an electrode. Examples of the extraction electrode include electrode parts such as connectors and crimp terminals. The electrode component can be bonded to the piezoelectric fiber structure by brazing such as soldering, a conductive bonding agent, or the like.

  Hereinafter, the present disclosure will be described in more detail with reference to examples. However, the present disclosure is not limited to the following examples unless the gist of the present disclosure is exceeded.

[Example 1]
<Fabrication of thread-like piezoelectric body>
(Production of monofilament yarn)
As the helical chiral polymer (A), polylactic acid (melting point: 170 ° C., heat of fusion: 38 J / g, molar ratio of L-lactic acid / D-lactic acid is 98.5 / 1.5 (the L-lactic acid content is 98. 5 mol%) and a number average molecular weight of 85,000).
Further, as the helical chiral polymer (B), polylactic acid (melting point: 170 ° C., heat of fusion: 38 J / g, molar ratio of D-lactic acid / L-lactic acid is 98.5 / 1.5 (the content of D-lactic acid is 98.5 mol%) and a number average molecular weight of 85,000).
The above two types of polylactic acid were respectively supplied to an extruder type melt spinning machine, and melt kneaded. From the 2C-shaped spinneret shown in FIG. 5, the two types of polylactic acid after melt-kneading are hollow cylindrical at a spinning temperature of 225 ° C., the half of the cylindrical part is the helical chiral polymer (A), and the other half of the cylindrical part is After obtaining melt spinning composed of the helical chiral polymer (B), the yarn was cooled and an oil agent was applied. Subsequently, without stretching once, it was stretched between hot rollers heated to 80 ° C. and scraped off. Thereby, a thread-like piezoelectric body (monofilament thread, thread-like fiber) having a total fineness of 295 dtex (20th: major axis diameter: 2.7 μm) was produced.

<S-wound twisted yarn of filamentous piezoelectric body>
The bundle of thread-like piezoelectric bodies obtained as described above is twisted so that the bundle is wound left-handed (S winding) with respect to the spiral axis and oriented in a direction of 45 ° with respect to the spiral axis (spiral angle 45 °). Winding to obtain a piezoelectric fiber structure. The number of twists of the twisted yarn (twist number) was visually observed to be about 10 turns per 10 mm with a stereomicroscope, and the number of twists per meter in this example was 1000 turns (1000 T / m). . Note that “left-handed (S-wound)” means that when viewed from one end of the central axis (spiral shaft) (the right-end side in the case of FIG. 2), the thread-like piezoelectric body is left-handed (reversely wound) from the near side to the far side. It means winding in a clockwise direction.

1 Area (A)
2 Region (B)
3 Hollow part 10, 20 Piezoelectric fiber structure 16 Insulating yarn 30 Piezoelectric knitted fabric 100 Piezoelectric fiber

Claims (14)

A region (A) containing a helical chiral polymer (A) having optical activity;
The helical chiral polymer (A) is different in chirality from the region (B) including the region (B) including the optically active helical chiral polymer (B),
Piezoelectric fiber having   The piezoelectric fiber according to claim 1, wherein the region (A) and the region (B) are located along a length direction of the piezoelectric fiber.   The piezoelectric fiber according to claim 1 or 2, wherein the piezoelectric fiber is a hollow fiber, and the region (A) and the region (B) constitute a cylindrical portion of the hollow fiber. The helical chiral polymer (A) and the helical chiral polymer (B) are polylactic acid polymers having a main chain containing a repeating unit represented by the following formula (1). The piezoelectric fiber according to any one of the above.
The helical chiral polymer (A) contains more than 50 mol% of an L-form component as a structural unit,
The piezoelectric fiber according to any one of claims 1 to 4, wherein the helical chiral polymer (B) includes more than 50 mol% of a D-form component as a structural unit. The helical chiral polymer (A) contains 90 mol% or more of an L-form component as a structural unit,
The piezoelectric fiber according to any one of claims 1 to 5, wherein the helical chiral polymer (B) includes 90 mol% or more of a D-form component as a structural unit.   A piezoelectric fiber structure in which the piezoelectric fiber according to any one of claims 1 to 6 is spirally wound.   The piezoelectric fiber structure according to claim 7, wherein the region (A) and the region (B) are wound at an angle of 15 ° to 75 ° with respect to the helical axis.   The piezoelectric fiber structure according to claim 8, wherein the region (A) and the region (B) adjacent to each other by being spirally wound are in contact with each other. It has a woven fabric structure consisting of warp and weft,
The piezoelectric fabric in which at least one of the warp and the weft includes the piezoelectric fiber structure according to any one of claims 7 to 9.   A piezoelectric knitted fabric comprising a knitted fabric structure including the piezoelectric fiber structure according to any one of claims 7 to 9.   A piezoelectric device comprising the piezoelectric fabric according to claim 10 or the piezoelectric knitted fabric according to claim 11.   A force sensor comprising the piezoelectric fiber structure according to any one of claims 7 to 9.   An actuator provided with the piezoelectric fiber structure of any one of Claims 7-9.