Piezoelectric fiber composite and piezoelectric clothing

Abstract

The piezoelectric fiber composite (1) is characterized in that it comprises: a substrate portion (2); a piezoelectric fiber assembly (3) composed of piezoelectric fibers (31, 32) that generate electric charge due to energy from the outside and have a different expansion and contraction rate from the substrate portion (2); and a joining portion (4) that joins the substrate portion (2) and the piezoelectric fiber assembly (3).

Description

Technical Field

[0001] The present invention relates to a piezoelectric fiber composite and a piezoelectric clothing having antibacterial properties. Background Art

[0002] In the past, a piezoelectric fabric formed by yarn containing a piezoelectric substrate has been proposed (see Patent Document 1). The piezoelectric fabric described in Patent Document 1 is a fabric that exhibits a piezoelectric effect due to external stimulation (such as physical force). In addition, a fabric that exhibits antibacterial properties due to external energy has been proposed (see Patent Document 2).

[0003] Patent Document 1: International Publication No. 2017 / 111108

[0004] Patent Document 2: Japanese Patent No. 6292368

[0005] However, it is desired that the cloth (piezoelectric fabric) that develops antibacterial properties develops antibacterial properties with less energy. Summary of the invention

[0006] Therefore, an object of one embodiment of the present invention is to provide a piezoelectric fiber composite that exhibits antibacterial properties with relatively low energy.

[0007] A piezoelectric fiber composite according to one embodiment of the present invention comprises: a substrate portion; a piezoelectric fiber assembly composed of piezoelectric fibers that generate electric charge due to energy from the outside and whose expansion and contraction rate is different from that of the substrate portion; and a joining portion that joins the substrate portion and the piezoelectric fiber assembly.

[0008] A piezoelectric fiber composite according to an embodiment of the present invention comprises: a base material; a piezoelectric fiber assembly composed of piezoelectric fibers that generate electric charges due to energy from the outside; and a plurality of joints that join the base material and the piezoelectric fiber assembly. When in use, the piezoelectric fiber assembly can be extended between at least two of the joints.

[0009] Furthermore, when the piezoelectric fiber composite is used for clothing, for example, the term "when in use" means when the piezoelectric fiber composite is being worn.

[0010] It is known that the proliferation of bacteria and fungi can be suppressed by electric fields (for example, see "Microbial Control - Science and Engineering by Tetsuaki Tsuchito, Hiroki Korei, Eiaki Matsuoka, Junichi Koizumi, Kodansha". In addition, for example, see "Koichi Takagi, Application of High Voltage Plasma Technology in Agriculture and Food", J.HTSJ, Vol.51, No.216). In addition, there is a situation where a current flows in a current path formed by moisture or the like or in a circuit formed by a micro-discharge phenomenon due to the potential generated by the electric field. It is conceivable that the fungi are weakened by the current and the proliferation of the fungi is suppressed. When receiving energy from the outside, the piezoelectric fiber composite of one embodiment of the present invention generates an electric field between at least two piezoelectric fibers that have different potentials when an electric charge is generated, or generates an electric field between the piezoelectric fiber and the object having the specified potential when the piezoelectric fiber composite is close to an object having a specified potential (including a ground potential) such as a human body. Alternatively, when receiving energy from the outside, the piezoelectric fiber composite of one embodiment of the present invention generates a current through moisture or the like between at least two piezoelectric fibers that have different potentials when an electric charge is generated, or generates a current through moisture such as sweat or the like between the piezoelectric fiber and the object having the specified potential when the piezoelectric fiber composite is close to an object having a specified potential (including a ground potential) such as a human body.

[0011] Therefore, the piezoelectric fiber composite of one embodiment of the present invention exhibits antibacterial properties based on the following reasons. The piezoelectric fiber composite is directly affected by the electric field or current generated when it is applied to articles with a specified electric potential such as those close to the human body (such as clothing, medical supplies such as masks, or filters used in electrical products), which hinders the cell membrane of fungi and the electron transfer system used to maintain the life of fungi, thereby killing fungi or weakening fungi. In addition, in the piezoelectric fiber composite, there is a situation where the oxygen contained in the water is changed into active oxygen due to the electric field or current. Or, in the piezoelectric fiber composite, there is a situation where oxygen free radicals are generated in the cells of the bacteria due to the stress environment formed by the presence of the electric field or current. In the piezoelectric fiber composite, fungi are killed or weakened by the action of active oxygen containing these free radicals. In addition, in the piezoelectric fiber composite, there is also a situation where the above reasons are combined to exert antibacterial effects. In addition, the "antibacterial" mentioned in the present invention is a concept that includes both the effect of weakening fungi and the effect of killing fungi.

[0012] The piezoelectric fiber composite of one embodiment of the present invention allows the piezoelectric fiber assembly to be bonded to the substrate portion in a state where the piezoelectric fiber assembly is in its natural length or stretched beyond its natural length. Therefore, even when a small load is applied to the piezoelectric fiber composite, the load is efficiently transferred to the piezoelectric fiber assembly, thereby being able to exhibit antibacterial properties with a small amount of energy.

[0013] According to one embodiment of the present invention, a piezoelectric fiber composite that exhibits antibacterial properties with relatively low energy can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a structural diagram showing an example of the structure of a piezoelectric fiber composite.

[0015] Figure 2 (A) is a schematic diagram showing an example of a piezoelectric fiber assembly (a state where the piezoelectric fibers are not stretched). Figure 2 (B) is a schematic diagram showing another example of the piezoelectric fiber assembly (a state in which the piezoelectric fibers are stretched).

[0016] Figure 3 (A) is a partial exploded view showing an example of the structure of a piezoelectric fiber. Figure 3 (B) is Figure 3 (A) is a cross-sectional view of the AA line, Figure 3 (C) is a partial exploded view showing another example of the structure of the piezoelectric fiber. Figure 3 (D) is Figure 3 (C) is a cross-sectional view along line BB.

[0017] Figure 4 (A) is a diagram showing an example of the relationship between the uniaxial stretching direction of polylactic acid, the electric field direction, and the deformation of the piezoelectric fiber. Figure 4 (B) is a diagram showing another example of the relationship between the uniaxial stretching direction of polylactic acid, the electric field direction, and the deformation of the piezoelectric fiber.

[0018] Figure 5 (A) is a diagram showing an example of shear stress (shear stress) generated in each fiber when tension is applied to the piezoelectric fiber. Figure 5 (B) is a diagram showing another example of shear stress (shear stress) generated in each fiber when tension is applied to the piezoelectric fiber.

[0019] Figure 6 This is a diagram showing an example of the electric field of a piezoelectric fiber assembly.

[0020] Figure 7 This is an explanatory diagram showing an example of changes in stress with respect to the passage of time when a load is applied to a piezoelectric fiber assembly.

[0021] Figure 8 This is a schematic diagram showing socks to which the piezoelectric fiber composite is applied.

[0022] Fig. 9 This is a structural diagram showing an example of a piezoelectric fiber composite according to Modification 1.

[0023] Fig.10 This is a schematic diagram showing a sanitary product to which the piezoelectric fiber composite according to Modification 1 is applied.

[0024] Fig.11 This is a structural diagram showing an example of a piezoelectric fiber composite according to Modification Example 2.

[0025] Fig.12 This is a structural diagram showing an example of a piezoelectric fiber composite according to Modification 3. DETAILED DESCRIPTION

[0026] A piezoelectric fiber composite 1 according to an embodiment will be described with reference to the drawings. Figure 1 1 is a structural diagram showing an example of a piezoelectric fiber composite 1. Figure 1 As shown, the piezoelectric fiber composite 1 includes a substrate 2, a piezoelectric fiber assembly 3, and a plurality of ( Figure 1 The piezoelectric fiber composite 1 has a two-layer structure in which a piezoelectric fiber assembly 3 is arranged on a main surface (one surface) of a substrate portion 2, for example.

[0027] The substrate portion 2 is, for example, a cotton cloth (for example, a woven fabric, a fabric, or a non-woven fabric) composed of fibers (fiber filaments). The expansion coefficient of the substrate portion 2 is lower than that of the piezoelectric fiber assembly 3. In other words, even if external energy (for example, tension P1) is applied to the substrate portion 2, it is not easy to stretch (deform) more than the piezoelectric fiber assembly 3. Since the substrate portion 2 is not easy to expand and contract, the piezoelectric fiber composite 1 can reduce damage such as rupture due to the application of external energy. The substrate portion 2 is constructed as described above, so that the piezoelectric fiber composite 1 can be used in thinner structures such as clothing and cover plates.

[0028] In addition, the substrate portion 2 may also be composed of fibers (filaments) formed of a material with a low rate of expansion and contraction. In addition, the substrate portion 2 may also be a nonwoven fabric, etc., formed so that the rate of expansion and contraction becomes low through its structure. In addition, the substrate portion 2 may also be formed of a monofilament or a multifilament. Furthermore, the substrate portion 2 is not limited to the example of cotton cloth composed of fibers, but may also be paper or a resin or metal formed in a sheet shape. In addition, the substrate portion 2 is not limited to a sheet shape such as cotton cloth, but may also be formed into a shape other than a sheet shape, such as a thick plate shape. In addition, the substrate portion 2 may also be formed into a rectangular or frame shape, for example.

[0029] The plurality of joints 4 join the substrate 2 and the piezoelectric fiber assembly 3. The plurality of joints 4 join (fix) the piezoelectric fiber assembly 3 to the substrate 2 by suturing or the like. The plurality of joints 4 join the piezoelectric fiber assembly 3 to the substrate 2, for example, at both ends of one direction (extension direction) E1 of the piezoelectric fiber assembly 3. The plurality of joints 4 are preferably arranged to face each other in the extension direction E1 of the piezoelectric fiber assembly 3.

[0030] Figure 2 (A) is a schematic diagram showing an example of the piezoelectric fiber aggregate 3 according to the present embodiment (a state where the piezoelectric fibers 31 and the piezoelectric fibers 32 are not stretched). Figure 2 (B) is a schematic diagram showing another example of the piezoelectric fiber assembly 3 (a state in which the piezoelectric fibers 31 and the piezoelectric fibers 32 are stretched). Figure 3 (A) is a partial exploded view showing an example of the structure of the piezoelectric fiber 31 constituting the piezoelectric fiber assembly 3 . Figure 3 (B) is Figure 3 (A) is a cross-sectional view of the AA line. Figure 3 (C) is a partial exploded view showing an example of the structure of the piezoelectric fiber 32 . Figure 3 (D) is Figure 3 (C) is a cross-sectional view along line BB.

[0031] like Figure 1 As shown in FIG. 1 , the piezoelectric fiber assembly 3 is able to stretch and expand (stretch) between the plurality of joints 4 that face each other in the stretching direction E1. Figure 2 (A) and Figure 2 As shown in (B), the piezoelectric fiber assembly 3 is composed of piezoelectric fibers 31 and piezoelectric fibers 32. The piezoelectric fiber assembly 3 is a woven fabric made by weaving the piezoelectric fibers 31 and the piezoelectric fibers 32 as braided yarns. The piezoelectric fiber assembly 3 is expanded and contracted by external energy. For example, if a tension P1 is applied, the piezoelectric fiber assembly 3 is expanded and contracted. Figure 2 The state shown in (A) is Figure 2 In this way, the piezoelectric fiber assembly 3 is configured to be easily stretched in the stretching direction E1 when the tension P1 is applied.

[0032] Here, the piezoelectric fibers 31 and 32 are described in detail. The piezoelectric fibers 31 and 32 are respectively Figure 3 (A) Figure 3 (B) Figure 3 (C) and Figure 3 As shown in (D), the structure is composed of multiple ( Figure 3 (A) Figure 3 (B) Figure 3 (C) and Figure 3 (D) is a yarn (multifilament yarn) formed by twisting 7 piezoelectric fibers 300. Figure 3 As shown in (A), the piezoelectric fiber 31 is a right-handed yarn (hereinafter referred to as S yarn) in which the fiber filament 300 is twisted right-handedly. Figure 3 As shown in (C), the piezoelectric fiber 32 is a left-handed yarn (hereinafter referred to as a Z yarn) in which the fiber filament 300 is twisted in a left-handed manner.

[0033] In addition, as an example, the piezoelectric fiber 31 and the piezoelectric fiber 32 are each a piezoelectric fiber assembly in which seven fiber filaments 300 are twisted, but the number of fiber filaments 300 is not limited thereto and is actually appropriately set according to the application and the like.

[0034] like Figure 3 (B) and Figure 3 As shown in (D), the fiber filament 300 is a fiber with a circular cross-section. The fiber filament 300 is a charge generating fiber (charge generating yarn) that generates an electric charge by applying external energy. For example, by applying tension P1 to the piezoelectric fiber 31 or the piezoelectric fiber 32, the fiber filament 300 generates an electric charge. The fiber filament 300 is composed of a functional polymer (for example, a piezoelectric polymer). As a piezoelectric polymer, for example, polylactic acid (PLA) can be cited. In addition, polylactic acid (PLA) is a piezoelectric polymer that does not have thermoelectricity. Polylactic acid has piezoelectricity by being uniaxially stretched. Polylactic acid exists in PLLA, which is polymerized by L-body monomers, and PDLA, which is polymerized by D-body monomers. In addition, the fiber filament 300 may also include structures other than the functional polymer as long as it does not hinder the function of the functional polymer. In addition, the fiber filament 300 is not limited to a structure with a circular cross-section.

[0035] In addition, polylactic acid is a chiral polymer with a helical structure in the main chain. If polylactic acid is uniaxially stretched to orient the molecules, it has piezoelectricity. If further heat treatment is performed to increase the crystallinity, the piezoelectric constant becomes higher. Polylactic acid has piezoelectricity due to the orientation of the molecules formed by stretching, and does not require polarization treatment like other piezoelectric polymers or piezoelectric ceramics such as PVDF (vinylidene fluoride). The piezoelectric constant of uniaxially stretched polylactic acid is about 5 to 30 pC / N, which is a very high piezoelectric constant among polymers. In addition, the piezoelectric constant of polylactic acid does not change over time and is extremely stable.

[0036] Figure 4 (A) is a diagram showing an example of the relationship between the uniaxial stretching direction 900 of L-phase polylactic acid (PLLA), the electric field direction, and the deformation of the fiber filament 300 . Figure 4 (B) is a diagram showing another example of the relationship between the uniaxial stretching direction 900 of L-body polylactic acid, the electric field direction, and the deformation of the fiber filament 300. Figure 4 (A) and Figure 4 (B) is a diagram in which the fiber filament 300 is assumed to be in a film shape as a model.

[0037] For the fiber filament 300 composed of uniaxially stretched polylactic acid, when the thickness direction is defined as the first axis, the uniaxial stretching direction 900 is defined as the third axis, and the direction orthogonal to both the first axis and the third axis is defined as the second axis, the fiber filament 300 has a d 14 and d 25 Therefore, when the fiber filament 300 composed of uniaxially stretched polylactic acid is deformed in a direction of 45 degrees with respect to the uniaxial stretching direction 900, electric charge is generated most efficiently.

[0038] The fiber filament 300 is PLLA, such as Figure 4 As shown in (A), when the fiber filament 300 is contracted in the direction of the first diagonal line 910A and stretched in the direction of the second diagonal line 910B orthogonal to the first diagonal line 910A, an electric field is generated in the direction from the inner side to the outer side of the paper. That is, the fiber filament 300 generates negative charges on the outer side of the paper. Figure 4 As shown in (B), when the fiber filament 300 is stretched in the direction of the first diagonal line 910A and contracted in the direction of the second diagonal line 910B, electric charges are also generated, but the polarity is opposite, and an electric field is generated in the direction from the surface of the paper toward the back side. That is, the fiber filament 300 generates positive charges on the outside of the paper.

[0039] The uniaxial stretching direction 900 of the fiber filament 300 is aligned with or parallel to the axial direction of the fiber filament 300. Figure 3 As shown in (A), the uniaxial stretching direction 900 of the fiber filament 300 of the piezoelectric fiber 31 is in a state of being tilted leftward on the paper surface relative to the axial direction 30A of the piezoelectric fiber 31. Figure 3 As shown in (C) , the uniaxial stretching direction 900 of the fiber filament 300 of the piezoelectric fiber 32 is in a state of being inclined rightward on the paper surface with respect to the axial direction 30B of the piezoelectric fiber 32 .

[0040] The inclination of the uniaxial stretching direction 900 of the fiber filament 300 relative to the axial directions 30A and 30B of the piezoelectric fiber 31 and the piezoelectric fiber 32 depends on the number of twists of the piezoelectric fiber 31 or the piezoelectric fiber 32. In other words, the inclination of the uniaxial stretching direction 900 relative to the axial directions 30A and 30B of the piezoelectric fiber 31 and the piezoelectric fiber 32 is not limited to Figure 3 (A) and Figure 3The inclination of the uniaxial stretching direction 900 with respect to the axial direction 30A of the piezoelectric fiber 31 may be at least intersecting with the axial direction 30A of the piezoelectric fiber 31. In addition, the inclination of the uniaxial stretching direction 900 with respect to the axial direction 30B of the piezoelectric fiber 32 may be at least intersecting with the axial direction 30B of the piezoelectric fiber 32.

[0041] Figure 5 (A) is a diagram showing a shear stress (shear stress) S1 generated in each fiber filament 300 when a tension P1 is applied to the piezoelectric fiber 31 . Figure 5 (B) is a diagram showing the shear stress (shear stress) S1 generated in each fiber filament 300 when the tension P1 is applied to the piezoelectric fiber 32. Figure 5 The tension P1 shown in (A) is a force that pulls the piezoelectric fiber 31 in the axial direction 30A of the piezoelectric fiber 31 and in the direction opposite to the axial direction 30A. Figure 5 The tension P1 shown in (B) is a force that pulls the piezoelectric fiber 32 toward the axial direction 30B of the piezoelectric fiber 32 and in the direction opposite to the axial direction 30B. In addition, the angle A1 is the angle of deformation of the piezoelectric fiber 31 relative to the uniaxial stretching direction 900 of each fiber filament 300 when the tension P1 is applied. And, the angle A2 is the angle of deformation of the piezoelectric fiber 32 relative to the uniaxial stretching direction 900 of each fiber filament 300 when the tension P1 is applied.

[0042] like Figure 5 As shown in (A), when a tension P1 is applied to the piezoelectric fiber 31 of the S yarn and deformation occurs in a direction that forms an angle A1 relative to the uniaxial stretching direction 900 of the fiber filament 300, negative charges are generated on the surface of the piezoelectric fiber 31 and positive charges are generated on the inside. More specifically, when a tension P1 is applied to the piezoelectric fiber 31, a shear stress S1 acts on the fiber filament 300. As a result, the fiber filament 300 shortens in a direction corresponding to the first diagonal line 910A and stretches in a direction corresponding to the second diagonal line 910B (see Figure 4 Therefore, negative charges are generated on the surface of the piezoelectric fiber 31, and positive charges are generated inside.

[0043] In addition, if Figure 5 As shown in (B), when a tension P1 is applied to the piezoelectric fiber 32 of the Z yarn and a deformation is generated in a direction forming an angle A2 relative to the uniaxial stretching direction 900 of the fiber filament 300, positive charges are generated on the surface of the piezoelectric fiber 32 and negative charges are generated inside. More specifically, when a tension P1 is applied to the piezoelectric fiber 32, a shear stress S1 acts on the fiber filament 300, stretching it in a direction relative to the first diagonal line 910A and shortening it in a direction corresponding to the second diagonal line 910B (see Figure 4 (B)). As a result, positive charges are generated on the surface of the piezoelectric fiber 32, and negative charges are generated inside.

[0044] In addition, the direction corresponding to the second diagonal line 910B is a direction parallel to the direction in which the tension P1 is applied. In addition, the shear stress S1 is a force acting in a direction parallel to the tension P1.

[0045] Therefore, when a tension P1 is applied to the piezoelectric fiber assembly 3 , each fiber filament 300 in the piezoelectric fiber 31 and the piezoelectric fiber 32 generates electric charge due to shear stress, thereby generating an electric field.

[0046] Figure 6 1 is a diagram showing an example of the electric field in the piezoelectric fiber 31 and the piezoelectric fiber 32 . Figure 6 The arrows shown indicate the direction of the electric field.

[0047] When a tension P1 is applied to the piezoelectric fiber assembly 3, Figure 6 As shown in FIG. 1 , if the piezoelectric fiber 31 as the S yarn and the piezoelectric fiber 32 as the Z yarn are brought close to each other, a larger electric field can be generated between the piezoelectric fiber 31 and the piezoelectric fiber 32. When the piezoelectric fiber 31 and the piezoelectric fiber 32 are brought close to each other, the electric field leaks into the air and is synthesized. The piezoelectric fiber assembly 3 is a woven fabric in which the piezoelectric fiber 31 and the piezoelectric fiber 32 composed of the piezoelectric fiber filaments 300 are used as the woven yarn, so that a larger electric field can be generated between the piezoelectric fiber 31 and the piezoelectric fiber 32 compared with the case where the piezoelectric fiber 31 or the piezoelectric fiber 32 is used alone.

[0048] As mentioned above, it is known that the proliferation of bacteria and fungi can be suppressed by electric fields. In addition, there is a situation where the electric potential generated by the electric field causes the current to flow in a current path formed by moisture or the like, or in a circuit formed by a tiny discharge phenomenon or the like. It is believed that the fungi are weakened by the current and the proliferation of the fungi is suppressed. In addition, the fungi referred to in this embodiment include bacteria, fungi, archaea, or microorganisms such as mites and fleas.

[0049] Thus, the piezoelectric fibers 31 and 32 are stretched by external energy (tension P1), thereby generating an electric field in the piezoelectric fiber assembly 3. In other words, the piezoelectric fiber assembly 3 composed of the piezoelectric fibers 31 and 32 expands and contracts by external energy, thereby exhibiting antibacterial properties.

[0050] However, in order to make the piezoelectric fiber assembly 3 exhibit antibacterial properties with relatively small external energy, it is sufficient to efficiently transmit the external energy to the fiber filaments 300. For this purpose, the piezoelectric fiber assembly 3 is fixed to the base material portion 2 via at least two joint portions 4. Figure 2As shown in (B), the piezoelectric fiber assembly 3 maintains a state of being stretched in the stretching direction E1 due to the tension P2. While the piezoelectric fiber assembly 3 maintains a state of being stretched due to the tension P2 (hereinafter, simply referred to as the stretched state), the piezoelectric fibers 31 and 32 are stretched and contracted by a small external energy.

[0051] The piezoelectric fiber assembly 3 is in a state of being stretched by a tension P2 of, for example, 0.5 N or more. Figure 1 As shown, the piezoelectric fiber assembly 3 is bonded to the base material portion 2 in a state where a desired external energy (e.g., load (tension) P2) is applied. The piezoelectric fiber assembly 3 is stretched due to the tension P2, and the stretching degree is increased by further pulling by the tension P1, so that the piezoelectric fibers 31 and the piezoelectric fibers 32 are further stretched in the stretching direction E1. For example, when the piezoelectric fibers 31 and the piezoelectric fibers 32 are stretched due to the tension P2 of 0.5N or more, if further external energy (e.g., tension P1) is applied, the tension P1 is directly transmitted to the piezoelectric fibers 31 and the piezoelectric fibers 32. In addition, the piezoelectric fiber assembly 3 may be stretched and bonded to the base material portion 2 when the tension P2 is applied when the piezoelectric fiber assembly 3 is worn.

[0052] Compared with the state where the piezoelectric fibers 31 and 32 are not stretched due to the tension P2, the piezoelectric fibers 31 and 32 are stretched due to a small external energy when stretched due to the tension P2. As a result, the piezoelectric fiber composite 1 stretches and contracts the piezoelectric fibers 31 and 32 due to a small external energy when the piezoelectric fiber assembly 3 is stretched. Moreover, in the piezoelectric fiber composite 1, when the piezoelectric fiber assembly 3 is stretched, the piezoelectric fibers 31 and 32 generate electric charges due to the stretching formed by the small external energy, thereby generating an electric field, thereby exhibiting antibacterial properties.

[0053] For example, when the piezoelectric fiber complex 1 is used for clothing (piezoelectric clothing), when the wearer wears the piezoelectric clothing, the piezoelectric fiber assembly 3 is stretched due to a tension P2 of more than 0.5N. The piezoelectric clothing to which the piezoelectric fiber complex 1 is applied exhibits antibacterial properties due to the energy of the wearer's tiny movements, etc. In addition, for example, when the piezoelectric fiber complex 1 is used for a mask, when the wearer wears the piezoelectric mask, the piezoelectric fiber assembly 3 is stretched due to a tension P2 of more than 0.5N. The piezoelectric mask expands and contracts due to a small amount of energy generated by the wearer's breathing, etc. The piezoelectric mask is stretched by a small amount of energy generated by the wearer's breathing, etc., thereby generating electric charges and generating an electric field, thereby exhibiting antibacterial properties.

[0054] in addition, Figure 7This is an explanatory diagram showing an example of changes in stress with time in a state where a predetermined load is applied to the piezoelectric fiber aggregate 3 for 18 hours and both ends in the extension direction are fixed. Figure 7 The vertical axis of the graph is stress (in MPa) and the horizontal axis is the elapsed time (in hours). Figure 7 As shown, if a load is applied to the piezoelectric fiber assembly 3, stress corresponding to the load is generated. The stress generated by the piezoelectric fiber assembly 3 gradually decreases over time. The stress applied to the piezoelectric fiber assembly 3 gradually decreases and increases and decreases slightly. In other words, in the state where the piezoelectric fiber assembly 3 is stretched, the piezoelectric fibers 31 and the piezoelectric fibers 32 repeat slight expansion and contraction in order to be expressed by the change in the stress. In this way, when the piezoelectric fiber assembly 3 is stretched, the piezoelectric fibers 31 and the piezoelectric fibers 32 expand and contract, thereby generating an electric field in the piezoelectric fiber assembly 3, showing antibacterial properties. In addition, the "antibacterial" mentioned in this embodiment is a concept that includes both the effect of weakening fungi and the effect of killing fungi.

[0055] Thus, for example, the piezoelectric fiber assembly 3 in the stretched state generates an electric field by a small deformation of the piezoelectric fiber assembly 3 caused by a small movement of the wearer. In addition, the piezoelectric fiber assembly 3 in the stretched state generates an electric field by applying a small external force energy in the environment, such as vibration, when used. Based on the above, the piezoelectric fiber composite 1 exhibits antibacterial properties by a small amount of energy in the stretched state.

[0056] In addition, the piezoelectric fiber assembly 3 may be fixed to the base material portion 2 via the joint portion 4 so that it does not stretch when the user (wearer) is not using (wearing) it, but stretches during use (wearing). Thus, the piezoelectric fiber composite 1 stretches in accordance with the wearer's use state or use form, thereby providing a sense of fit to the wearer.

[0057] In addition, the piezoelectric fiber assembly 3 may be fixed to the base material 2 by the joint 4 in an extended state. In other words, the piezoelectric fiber assembly 3 may be fixed to the base material 2 by the joint 4 in a state extended longer than the natural length. Thus, the user can use the piezoelectric clothing, piezoelectric sheet, piezoelectric filter, etc. to which the piezoelectric fiber composite 1 is applied without worrying about external energy such as tension during use. In addition, the natural length of the piezoelectric fiber assembly 3 is the length in a state where no load is applied to the piezoelectric fiber assembly 3.

[0058] In addition, when the piezoelectric fibers 31 and 32 are close to an object having a predetermined electric potential such as a human body through moisture such as sweat, an electric current flows, and therefore, there is a case where an antibacterial effect is directly exerted. In addition, there is a case where an antibacterial effect is indirectly exerted by free radical substances obtained by changing the oxygen contained in the water by the action of electric current and voltage, free radical substances generated by further interaction and catalysis with additives contained in the fibers, and other antibacterial chemical substances (amine derivatives, etc.). As free radical substances, the generation of superoxide anion radicals (active oxygen) or hydroxyl radicals is considered.

[0059] In addition, the piezoelectric fibers 31 and 32 generate an electric field due to the potential difference caused by the generated charges. This electric field also leaks into the nearby space and forms a coupled electric field with other parts. In addition, when the potential generated by the piezoelectric fibers 31 and 32 approaches a predetermined potential, for example, when the piezoelectric fibers 31 and 32 are close to an object having a predetermined potential (including a ground potential), such as a human body, an electric field is generated between the piezoelectric fibers 31 and 32 and the object.

[0060] Application examples of this embodiment will be described below.

[0061] A case where the piezoelectric fiber composite 1 is used in socks 5 will be described. Figure 8 Schematic diagram showing a sock 5 to which the piezoelectric fiber composite 1 is applied. Figure 8 As shown, the sock 5 is a piezoelectric clothing material in which the piezoelectric fiber composite 1 is applied to the heel portion 50. The heel portion 50 of the sock 5 is formed so that the piezoelectric fiber assembly 3 is on the body side of the wearer and the base material portion 2 is on the outside. In other words, the piezoelectric fiber composite 1 applied to the heel portion 50 of the sock 5 is a two-layer structure consisting of the piezoelectric fiber assembly 3 on the inside and the base material portion 2 on the outside. In addition, the portion (non-piezoelectric portion) 51 of the sock 5 other than the heel is formed of the same material as the base material portion 2.

[0062] The piezoelectric fiber assembly 3 is fixed to the base material 2 at both ends in the front-back direction by sewing or the like. The piezoelectric fiber assembly 3 is bonded to the base material 2 so as to be in a state of being stretched in the stretching direction E1 by a desired tension (for example, 0.5N or more) when the wearer wears the socks 5. The piezoelectric fiber assembly 3 generates an electric field in accordance with a slight movement of the wearer's heel while being stretched by the desired tension. Thus, the socks 5 using the piezoelectric fiber composite 1 in the heel portion 50 exhibit antibacterial properties with a small external energy.

[0063] The base material 2 is a strong cotton cloth that is not easily stretched (deformed). In this case, the base material 2 is present at the heel portion 50 of the sock 5, thereby reducing damage caused by friction, etc., compared with a case where the base material 2 is not present at the heel portion 50.

[0064] As a result, by applying the piezoelectric fiber composite 1 to the heel portion 50 of the socks 5, the socks 5 are less likely to be damaged in the heel portion 50 and exhibit antibacterial properties with less external energy.

[0065] Furthermore, the material of the non-piezoelectric portion 51 may be different from that of the base portion 2. Furthermore, the non-piezoelectric portion 51 and the base portion 2 may be formed integrally.

[0066] As described above, the piezoelectric fiber composite 1 can be applied to various clothing materials, medical components, or electrical products, etc. For example, the piezoelectric fiber composite 1 can be applied to various uses such as socks, underwear, gauze, masks, sanitary products (sanitary shorts, disposable diapers, cloth diapers, diaper covers, etc.), various filters (filters for water purifiers, air conditioners, or air purifiers, etc.), seats (seats for cars, trains, or airplanes, etc.).

[0067] Modifications of the piezoelectric fiber composite 1 are listed below. In addition, descriptions of the same structures as those of the above-mentioned piezoelectric fiber composite 1 are omitted.

[0068] Fig. 9 1 is a structural diagram showing an example of a piezoelectric fiber composite 1A according to Modification 1. Fig. 9 As shown, the piezoelectric fiber complex 1A is different from the above-mentioned piezoelectric fiber complex 1 in that it is composed of an elongation region 301 and a normal region 302. The elongation region 301 is a region that is elongated due to a desired load (for example, a tension P2 of 0.5N) when the wearer wears it (during use). The normal region 302 is a region other than the elongation region 301, and is a region that expands and contracts due to the movement of the wearer's body or the shape of the body. The joint 4 joins the piezoelectric fiber assembly 3 to the base material portion 2 at both ends of the elongation direction E1 of the elongation region 301 by sewing or the like.

[0069] An example in which the piezoelectric fiber composite 1A is used in sanitary pants (sanitary products) 6 will be described. Fig.10 Schematic diagram showing a sanitary product (sanitary pants) 6 to which the piezoelectric fiber composite 1A according to Modification 1 is applied. Fig.10As shown in FIG. 1 , the piezoelectric fiber assembly 3 is composed of an extension region 301 and a normal region 302. The extension region 301 is arranged at the lower part of the sanitary pants 6. The joint 4 joins the piezoelectric fiber assembly 3 to the base material portion 2 at both ends of the extension region 301 in the front-to-back direction. In other words, the extension region 301 is extended in the front-to-back direction between the two joints 4 in the front-to-back direction while the wearer is wearing it. The normal region 302 is appropriately expanded and contracted according to the wearer's movements, etc.

[0070] In the piezoelectric fiber complex 1A involved in modification example 1, while the wearer wears the sanitary shorts 6, the elongation region 301 is elongated, so that compared with the normal region 302, an electric field can be generated by smaller external energy to exert an antibacterial effect. In other words, in the piezoelectric fiber complex 1A involved in modification example 1, the normal region 302 expands and contracts according to the movement of the wearer's body, thereby generating an electric field and exhibiting antibacterial properties. In addition, the elongation region 301 expands and contracts by utilizing smaller external energy to the extent that the wearer is not aware of it, thereby generating an electric field and exhibiting antibacterial properties. In this way, the piezoelectric fiber complex 1A involved in modification example 1 more effectively exerts an antibacterial effect because the piezoelectric fiber assembly 3 is composed of the elongation region 301 and the normal region 302.

[0071] Fig.11 1 is a structural diagram showing an example of a piezoelectric fiber composite 1B according to Modification Example 2. Fig.11 As shown, the piezoelectric fiber composite 1B involved in modification example 2 is different from the above-mentioned piezoelectric fiber composite 1 and piezoelectric fiber composite 1A in that the plurality of joints 4 are arranged in a scattered manner in the planar direction of the extension region 301. By arranging the plurality of joints 4 in a scattered manner, the elasticity or flexibility of the piezoelectric fiber composite 1B is not impaired, and an electric field is generated by a relatively small external energy to exert an antibacterial effect. The plurality of joints 4 may also be arranged on one or more straight lines. In addition, the plurality of joints 4 may also be arranged in a zigzag shape (different from each other).

[0072] The piezoelectric fiber composite 1B involved in the modification example 2 has a plurality of joints 4, so that a small external energy is easily transmitted to the piezoelectric fibers 31 and the piezoelectric fibers 32. The piezoelectric fiber composite 1B involved in the modification example 2 has a plurality of joints 4, so that when the piezoelectric fiber assembly 3 is stretched between the joints 4, the antibacterial property is exhibited by the expansion and contraction due to the small external energy.

[0073] Fig.12 1 is a structural diagram showing an example of a piezoelectric fiber composite 1C according to Modification Example 3. Fig.12As shown, the piezoelectric fiber complex 1C involved in the modified example 3 is different from the above-mentioned piezoelectric fiber complex 1, piezoelectric fiber complex 1A and piezoelectric fiber complex 1B in that a joint portion 4 is configured to surround the piezoelectric fiber assembly 3 using two sets of parts 41 and 42 facing each other.

[0074] The two groups of parts 41 and 42 facing each other in the piezoelectric fiber composite 1C according to the modification 3 are bonded to the base material 2 so as to surround the piezoelectric fiber assembly 3. Therefore, relatively small external energy is easily transmitted to the piezoelectric fibers 31 and 32. Since the piezoelectric fiber composite 1C according to the modification 3 is fixed around the piezoelectric fiber assembly 3, the piezoelectric fiber assembly 3 exhibits antibacterial properties by expansion and contraction based on relatively small external energy, for example, when the piezoelectric fiber assembly 3 is stretched between the two groups of parts 41 facing each other.

[0075] In addition, the piezoelectric fiber assembly 3 may include yarns other than the S yarn that generates negative charges on the surface and the Z yarn that generates positive charges on the surface. By adjusting the usage of the Z yarn and the S yarn, the ratio of the polarity of the charges generated according to the application can be adjusted. In addition, the piezoelectric fiber 31 may include yarns (cotton yarn, etc.) that do not generate charges in addition to the Z yarn and the S yarn. Generally, piezoelectric yarns have a worse skin feel than cotton yarns, etc., so there is a situation where the skin is irritated when the wearer wears it. Therefore, by locally using yarns (cotton yarns, etc.) that do not generate charges on the piezoelectric fiber assembly 3, the skin feel of the piezoelectric fiber assembly 3 is improved, and the irritation of the piezoelectric fiber complexes 1, 1A, 1B, 1C to the skin is alleviated.

[0076] In addition, the piezoelectric fiber composites 1, 1A, 1B, and 1C may use Z yarns or S yarns alone. When Z yarns or S yarns are used alone, the piezoelectric fiber composites 1, 1A, 1B, and 1C also exhibit antibacterial properties.

[0077] In addition, even if there is only one joint portion 4, it is sufficient as long as it includes the facing portions. The joint portion 4 may be, for example, U-shaped.

[0078] In addition, the piezoelectric fiber composites 1, 1A, 1B, and 1C can also be used as a method for inhibiting bacteria on the body surface of animals other than humans. The piezoelectric fiber composite 3 is arranged to face at least a part of the skin of the animal, and the piezoelectric fiber composite 1, 1A, 1B, and 1C can inhibit the proliferation of bacteria on the body surface of the animal by the electric charge generated when an external force is applied to the piezoelectric fiber composite 3.

[0079] In addition, the fiber filament 300 can also be manufactured by the following methods, for example, a method of fiberizing a piezoelectric polymer by extrusion molding, a method of fiberizing a piezoelectric polymer by melt spinning (for example, a spinning / stretching method that includes separately performing a spinning process and a stretching process, a straight stretching method that combines a spinning process and a stretching process, a POY-DTY method that can also perform a false twisting process at the same time, or an ultra-high-speed spinning method that achieves high speed, etc.), a method of fiberizing a piezoelectric polymer by dry or wet spinning (for example, a phase separation method or a dry-wet spinning method that includes dissolving a polymer as a raw material in a solvent and extruding it from a nozzle to fiberize, a gel spinning method that maintains a solvent-containing state and uniformly fibers in a gel state, or a liquid crystal spinning method that uses a liquid crystal solution or a melt to fiberize, etc.), or a method of fiberizing a piezoelectric polymer by electrospinning, etc.

[0080] In addition, the joining portion 4 may join the piezoelectric fiber assembly 3 and the base member 2 using an adhesive or the like. Furthermore, the joining portion 4 may join the piezoelectric fiber assembly 3 and the base member 2 by heat pressing.

[0081] In addition, the piezoelectric fiber 31 or the piezoelectric fiber 32 is not limited to a knitted fabric using the fiber yarn 300 , and may be a woven fabric or a nonwoven fabric using the fiber yarn 300 .

[0082] The piezoelectric fiber 31 or the piezoelectric fiber 32 may be a yarn made of PDLA. When the yarn made of PDLA is used, the positive and negative charges generated on the surfaces of the piezoelectric fiber 31 and the piezoelectric fiber 32 are different from those when the yarn made of PLLA is used.

[0083] Finally, it should be considered that the description of the present embodiment is illustrative in all aspects and is not restrictive. The scope of the present invention is not shown by the above-mentioned embodiment, but by the claims. Moreover, the scope of the present invention is intended to include all changes within the meaning and scope equivalent to the claims.

[0084] Description of Reference Numerals

[0085] 1, 1A, 1B, 1C... piezoelectric fiber composite; 2... substrate portion; 3... piezoelectric fiber assembly; 4... joining portion; 5... socks (piezoelectric clothing); 6... sanitary shorts (sanitary products); 30A, 30B... axial direction; 31, 32... piezoelectric fiber; 41, 42... part; 50... heel portion; 51... non-piezoelectric portion; 300... fiber filament; 301... elongation region; 302... normal region; 900... uniaxial stretching direction; 910A... first diagonal line; 910B... second diagonal line; A1, A2... angles; E1... one direction (elongation direction); P1, P2... tension (external energy); S1... stress.

Claims

1. A piezoelectric fiber composite, characterized in that: have: a substrate portion formed in a sheet shape; a piezoelectric fiber assembly, which is composed of piezoelectric fibers that generate electric charge due to energy from the outside and has a different expansion and contraction rate from the base material portion; as well as a joining portion for joining the substrate portion and the piezoelectric fiber assembly, The piezoelectric fiber assembly is bonded to the base member in a state where the piezoelectric fiber assembly is extended beyond its natural length.

2. The piezoelectric fiber composite according to claim 1, characterized in that The joint portion has facing parts, The piezoelectric fiber assembly is capable of extending between the facing portions.

3. The piezoelectric fiber composite according to claim 1 or 2, characterized in that: The expansion and contraction rate of the substrate portion is lower than the expansion and contraction rate of the piezoelectric fiber assembly.

4. The piezoelectric fiber composite according to claim 1, characterized in that The piezoelectric fiber assembly is disposed on one surface of the base member.

5. The piezoelectric fiber composite according to claim 1, characterized in that The piezoelectric fiber assembly exhibits antibacterial properties due to energy from the outside.

6. The piezoelectric fiber composite according to claim 1, characterized in that The piezoelectric fiber assembly includes polylactic acid.

7. The piezoelectric fiber composite according to claim 1, characterized in that: The piezoelectric fiber includes a right-handed yarn and a left-handed yarn.

8. The piezoelectric fiber composite according to claim 7, characterized in that The right-handed yarn and the left-handed yarn are multifilament yarns.

9. A piezoelectric fiber composite, characterized in that: have: a substrate portion formed in a sheet shape; A piezoelectric fiber assembly, comprising piezoelectric fibers that generate electric charge due to energy from the outside; as well as A plurality of joints join the base member and the piezoelectric fiber assembly, the piezoelectric fiber assembly is joined to the base member in a state of being stretched longer than a natural length, and the piezoelectric fiber assembly can be stretched between at least two of the joints when in use.

10. The piezoelectric fiber composite according to claim 9, characterized in that The piezoelectric fiber assembly is disposed on one surface of the base member.

11. The piezoelectric fiber composite according to claim 9, characterized in that The piezoelectric fiber assembly exhibits antibacterial properties due to energy from the outside.

12. The piezoelectric fiber composite according to claim 9, characterized in that The piezoelectric fiber assembly includes polylactic acid.

13. The piezoelectric fiber composite according to claim 9, characterized in that The piezoelectric fiber includes a right-handed yarn and a left-handed yarn.

14. The piezoelectric fiber composite according to claim 13, characterized in that The right-handed yarn and the left-handed yarn are multifilament yarns.

15. A piezoelectric clothing material, characterized in that: A piezoelectric fiber composite according to any one of claims 1 to 14, The piezoelectric fibers are used in an extended state.

16. The piezoelectric clothing material according to claim 15, characterized in that The piezoelectric fiber assembly is disposed on the body side.

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