Patent Description:
Conventionally, many proposals have been made on an antibacterial nonwoven fabric and a cushioning material (hereinafter referred to as buffer material) (see <CIT>, <CIT>, <CIT>and <CIT>).

Antibacterial materials used in nonwoven fabrics or the like, however, may fail to keep excellent antibacterial action for a long time.

Further, the antibacterial materials may cause an allergic reaction due to chemicals or the like.

We have appreciated that it would be desirable to provide an antibacterial nonwoven member, an antibacterial nonwoven fabric, and an antibacterial buffer material which keep an antibacterial effect longer than conventional antibacterial materials and are more excellent in safety than chemicals or the like.

Conventionally, there has been known that an electric field can inhibit the growth of bacteria (see, for example, <NPL>. See also, for example, "<NPL>). A potential which produces the electric field may cause an electric current to flow in a current path formed due to humidity or the like, or in a circuit formed through a local phenomenon of microdischarge. The electric current may partially destroy cell membranes of bacteria to inhibit the growth of bacteria. The antibacterial nonwoven member of the present invention locally produces an electric field inside the nonwoven member due to electric charges generated when an external force is applied to the piezoelectric bodies. When it comes close to an object having a given potential (including a ground potential) such as a human body, an electric field is produced between the nonwoven member and the object. Alternatively, the antibacterial nonwoven member of the present invention allows an electric current to locally flow inside the nonwoven member through moisture such as perspiration. When it comes close to an object having a given potential (including a ground potential) such as a human body, an electric current is flown between the nonwoven member and the object. Therefore, the antibacterial nonwoven member of the present invention damages cell membranes of bacteria or an electron transfer system for maintaining bacteria life to thereby kill bacteria or weaken bacteria themselves due to a direct action of the electric field or current that is locally produced in the member, or due to a direct action of the electric field or current that is produced when applied to an object (clothes, hygienic materials, cushioning materials, etc.) used close to an object having a given potential such as a human body. Further, the electric field or current may convert oxygen contained in moisture into active oxygen species, or stress environment caused by the presence of the electric field or current may produce oxygen radicals in cells of bacteria. The action of the active oxygen species including these radicals can kill bacteria or weaken bacteria themselves. In addition, an antibacterial effect (effect of inhibiting the growth of bacteria) and a sterilizing effect may be produced in combination of the above reasons.

Since the nonwoven member according to the present invention produces an electric field by a piezoelectric effect, no power supply is required, and an electric shock may not occur. The life of the piezoelectric body lasts longer than the antibacterial effect of chemicals or the like. Further, the piezoelectric body may cause an allergic reaction less than chemicals.

<CIT> discloses a sleeping system comprising a mattress and an underblanket for the recumbent person or animal on the surface of, in which the underblanket consists of plastic yarn with piezo-electric particles dispersed in the threads. Particles with pyro-electric properties may also be dispersed in the plastic threads.

<CIT> discloses a nanofiber web piezoelectric material and a method of producing the same, wherein a spinning solution of polylactic acid (PLA) in a solvent is electrospun, yielding a nanofiber web, thereby exhibiting piezoelectric properties without additional drawing.

<CIT> relates to a method for producing a piezoelectric and pyroelectric fiber comprising: providing a fiber comprising a core having a core material and a surrounding material enclosing the core material, the core material comprises an electrically conductive flexible thermoplastic composite comprising at least one polymer and at least one conductive filler, and the surrounding material is a permanently polarizable polymer; stretching the fiber along an elongation direction of the fiber with a draw ratio sufficient to introduce beta-crystallites in the fiber; electrically grounding the core material; while the core material is grounded, passing the fiber through an annular poling element; and applying a voltage between the annular poling element and the core material sufficient to establish an electric field for corona poling, whereby the core material is exposed to the electric field electrically charging the surrounding material.

<CIT> discloses a technique for producing a piezoelectric material capable of producing piezoelectric properties by a tension applied in the axial direction by applying specific twists in the axial direction to a fibrous material comprising a piezoelectric polymer. Twists are applied through a driving unit to a fiber yarn continuously delivered from a yarn tube and comprising a piezoelectric polymer such as polylactic acid in the same direction or alternately with the opposite direction or in the direction randomly at a twisting angle within the range of <NUM>-<NUM> deg. from the axial direction and the yarn is then passed through a dry heating bath and a roller bath and wound with a winder to produce a piezoelectric material.

<CIT>, which is a document falling under Article <NUM>(<NUM>) EPC, discloses a cloth with an enhanced antibacterial property, and high safety. A charge-generating thread for bacterium-countermeasures including a charge-generating fiber is also disclosed. The charge-generating fiber generates a charge by energy from the outside of the fiber, and the charge-generating thread for bacterium-countermeasure restrains the proliferation of bacteria by the charge. <CIT> does not disclose a nonwoven member having a nonwoven mass in which piezoelectric yarns are formed.

The invention is defined in the independent claim to which reference should now be made.

The present invention can achieve an antibacterial nonwoven member and an antibacterial buffer material which keep an antibacterial effect longer than conventional antibacterial materials and are more excellent in safety than chemicals or the like.

Hereinafter, a plurality of embodiments for carrying out the invention will be described by way of some specific examples with reference to the accompanying drawings. The same parts are assigned the same reference symbols in all figures. In consideration of description of major points or easy understanding, embodiments are separately shown for convenience. It is, however, possible to partially replace or combine with configurations shown in different embodiments. In the second and subsequent embodiments, the description common to the first embodiment will be omitted and only different points will be described. In particular, the similar operation and effect by the similar configuration will not be described in each embodiment.

Although some examples are shown in the subsequent embodiments, the "nonwoven member" as used herein is a nonwoven member including a piezoelectric body, and examples thereof include nonwoven fabric or buffer material (wadding, cushioning material, pellet, mat, etc.).

Further, the "nonwoven member" in the present invention can be used as a nonwoven fabric or a buffer material in any applications requiring antibacterial and antifungal properties. The "nonwoven member" that may be used includes, for example, clothes (inner or insole for clothing, underwear, headwear, shoes, boots, etc.), sporting goods (inner materials for wear and gloves, gloves used for martial arts), kitchenware (sponge, dish towel), hygienic materials (mask, bandage, gauze, supporter), commodities (curtain, toilet seat sheet), sanitary supplies, various filters (water purifier, air conditioner, air purifier), various mats (for foot, for toilet), cushion members (seat for cars, electric cars, or airplanes, buffer material and exterior material for motorcycle helmets, sofa, pillow, futon, mattress, stuffed toy), pet goods (mat for pets, inner for pet clothing), and packaging materials (packing pellet, packing mat).

<FIG> is a schematic plan view of a nonwoven member <NUM> according to a first comparative example, and <FIG> is a plan view of a piezoelectric fiber <NUM> forming the nonwoven member <NUM>. The nonwoven member <NUM> is a nonwoven fabric. The nonwoven fabric is an example of the "nonwoven member" in the present invention.

The nonwoven member <NUM> includes a plurality of piezoelectric fibers <NUM>. The nonwoven member <NUM> of the present example is formed into a cloth (sheet) by intertwining the plurality of piezoelectric fibers <NUM>. The piezoelectric fiber <NUM> is an example of the "piezoelectric body".

The piezoelectric fiber <NUM> is made of, for example, a piezoelectric polymer. Some of the piezoelectric fibers <NUM> are pyroelectric and some are not. For example, polyvinylidene fluoride (PVDF) is pyroelectric and generates an electric charge due to temperature change. Polylactic acid (PLA) is a piezoelectric body not having pyroelectricity. Polylactic acid is uniaxially stretched to have piezoelectric properties. Polylactic acid includes PLLA in which an L-form monomer is polymerized, and PDLA in which a D-form monomer is polymerized.

A chiral polymer such as polylactic acid has a spiral structure in its main chain. The chiral polymer has piezoelectric properties when molecules are oriented by uniaxially stretching. The piezoelectric fiber <NUM> made of uniaxially stretched polylactic acid has d<NUM> and d<NUM> tensor components as piezoelectric strain constants when the thickness direction of the piezoelectric fiber <NUM> is defined as a first axis, the stretching direction <NUM> thereof is defined as a third axis, and a direction perpendicular to both the first and third axes is defined as a second axis. Accordingly, polylactic acid generates an electric charge when a strain occurs in a direction at an angle of <NUM>° to the uniaxially stretching direction.

<FIG> are views showing a relationship of a uniaxially stretching direction of polylactic acid, an electric field direction, and deformation of a piezoelectric film <NUM>.

As shown in <FIG>, when the piezoelectric film <NUM> shrinks in a direction of a first diagonal line 910A and stretches in a direction of a second diagonal line 910B perpendicular to the first diagonal line 910A, an electric field is produced in a direction from the back plane to the front plane of the paper. That is, the piezoelectric film <NUM> generates a negative electric charge on the front plane of the paper. As shown in <FIG>, even when the piezoelectric film <NUM> stretches in the first diagonal line 910A and shrinks in the second diagonal line <NUM>0B, an electric charge is generated, but the polarity is reversed, and an electric field is produced in a direction from the front plane to the back plane of the paper. That is, the piezoelectric film <NUM> generates a positive electric charge on the front plane of the page.

Since polylactic acid generates the piezoelectric properties due to molecular orientation processing by stretching, it does not need to be subjected to polling processing as do other piezoelectric polymers such as PVDF or piezoelectric ceramic. The uniaxially-stretched polylactic acid has a piezoelectric constant of approximately <NUM> to <NUM> pC/N, which is an extremely high piezoelectric constant among polymers. Further, the piezoelectric constant of the polylactic acid does not vary with time and is extremely stable.

The piezoelectric fiber <NUM> is a ribbon film made of polylactic acid having a flat elongated shape. As shown in <FIG>, the stretching direction <NUM> of the piezoelectric fiber <NUM> is oriented in the same direction as the longitudinal direction. Therefore, when shear stress is applied to the longitudinal direction of the piezoelectric fiber <NUM>, the piezoelectric fiber <NUM> becomes in a state shown in <FIG> and an electric charge of a polarity corresponding to the deformation of the surface is generated. Therefore, when a tension or the like is applied from outside to the nonwoven member <NUM> having a sheet shape formed by intertwining the plurality of piezoelectric fibers <NUM>, sliding deformation occurs in the piezoelectric fiber <NUM> (among the plurality of piezoelectric fibers <NUM>, one other than those of which the stretching direction is at an angle of <NUM>° or <NUM>° to the direction of the above-mentioned tension or the like) due to shear stress, which in turn generates a voltage. The voltage thus generated produces electric fields between the plurality of piezoelectric fibers <NUM>. In addition, when the plurality of piezoelectric fibers <NUM> come close to an object having a given potential (including a ground potential) such as a human body, an electric field is produced between the piezoelectric fibers and the object.

<FIG> is an outline view of a mask <NUM> including the nonwoven member <NUM>. As shown in <FIG>, the mask <NUM> includes the nonwoven member <NUM> and straps <NUM>.

In the nonwoven member <NUM>, the plurality of piezoelectric fibers <NUM> having a predetermined length are contained so that their longitudinal directions are at random angles. The plurality of piezoelectric fibers <NUM> are close to or overlapped with each other at a plurality of positions in the nonwoven member <NUM>. The piezoelectric fiber <NUM> has a width of, for example, approximately <NUM> to <NUM> and a thickness of, for example, approximately <NUM> to <NUM>. The piezoelectric fiber <NUM> also has a length of, for example, approximately <NUM> to <NUM>. These dimensions are design matters to be determined by a method of manufacturing the piezoelectric fiber <NUM> and are not limited thereto. The piezoelectric fiber <NUM> is made from a film obtained by stretching through a slit process. A piezoelectric polylactic film is generally made by longitudinally uniaxial stretching or transversely uniaxial stretching. The molecule of the piezoelectric polylactic film is oriented along the stretching direction. When each film is cut out from a raw film during the slit process, a film is cut into a ribbon piece at an angle larger than <NUM>° and smaller than <NUM>° relative to the molecular oriented direction (preferably an angle of <NUM>° relative to the molecular oriented direction), so that the ribbon film thus cut out generates an electric charge by stretching in the longitudinal direction. The piezoelectric fiber <NUM> may be such a ribbon film. A plurality of ribbon films thus cut out at any angle including <NUM>° and <NUM>° relative to the molecular oriented direction may be used as the piezoelectric fiber <NUM>. That is, the molecular orientation direction of the plurality of piezoelectric fibers <NUM> may be at random angles to the longitudinal direction. In this case, the piezoelectric fibers <NUM> that are cut out at any angle relative to the molecular oriented direction are present in the nonwoven member <NUM>. Therefore, among the plurality of piezoelectric fibers <NUM>, a piezoelectric fiber <NUM> where sliding deformation occurs due to an external force applied from outside effectively generates an electric charge. Accordingly, this configuration allows an effect described below to be uniformly exerted on an external force in any direction applied from outside.

It has been known that an electric field can inhibit the growth of bacteria (see, for example, <NPL>See also, for example, "<NPL>). A potential which produces the electric field may cause an electric current to flow in a current path formed due to humidity or the like, or in a circuit formed through a local phenomenon of microdischarge. The electric field or current may convert oxygen contained in moisture into active oxygen species, or stress environment caused by the presence of the electric field or current may produce oxygen radicals in cells of bacteria. The action of the active oxygen species including these radicals can kill bacteria or weaken the bacteria themselves. In addition, an antibacterial effect (effect of inhibiting the growth of bacteria) and a sterilizing effect may be produced in combination of the above reasons. The electric current may partially destroy cell membranes of bacteria to inhibit the growth of bacteria. The bacteria as used in this example include germs, fungi, or microorganism such as mites, fleas, or the like.

When the mask <NUM> is worn, the mask <NUM> is bent due to the movement by breathing, conversation, and the like at a high frequency, and such bending causes the nonwoven member <NUM> to be stretched. This produces voltages on the plurality of piezoelectric fibers <NUM> in the nonwoven member <NUM> and the electric field is generated between the plurality of the piezoelectric fibers <NUM>. Further, since the mask <NUM> is positioned close to a human body (skin), when an external force is applied to the nonwoven member <NUM> in the mask <NUM>, an electric field is generated between the human body and the nonwoven member <NUM>. Therefore, the electric field generated in the nonwoven member <NUM> or the electric field generated between the human body and the nonwoven member <NUM> directly exerts an antibacterial effect and an antifungal effect. In addition, the mask absorbs breathing, perspiration or moisture in the air to become a hotbed for growth of bacteria. The nonwoven member <NUM> is, however, capable of inhibiting the growth of bacteria and thus produces a remarkable effect as applications for antibacterial measure and measure against odor.

As described above, the piezoelectric fiber <NUM> generates a positive or negative electric charge when an external force is applied. This causes the piezoelectric fiber <NUM> to attract a substance having a positive electric charge (e.g., particles such as pollen) or a substance having a negative electric charge (e.g., harmful substances such as yellow dust). Therefore, it is possible for the mask <NUM> to attract fine particles such as pollen or yellow dust with the nonwoven member <NUM> including the piezoelectric fibers <NUM>.

The first embodiment shows an example in which the nonwoven member of the present invention is a buffer material.

<FIG> is an outline view of a nonwoven member <NUM> according to a first embodiment and <FIG> is an enlarged view of a DP1 portion shown in <FIG>.

The nonwoven member <NUM> includes a mass <NUM> containing a piezoelectric body. The mass <NUM> is composed of a piezoelectric yarn <NUM>, a piezoelectric yarn <NUM>, and a cotton <NUM>. The mass <NUM> is a cushioning material obtained by mixing the piezoelectric yarns <NUM> and <NUM> with the cotton <NUM> as shown in <FIG>. The nonwoven member <NUM> according to this embodiment is a cushioning material to be used in, for example, a cushion.

<FIG> is a partially exploded view showing a configuration of a piezoelectric yarn <NUM> and <FIG> is a partially exploded view showing a configuration of a piezoelectric yarn <NUM>. <FIG> is a plan view of the piezoelectric film <NUM>.

Each of the piezoelectric yarns <NUM> and <NUM> is made by winding the piezoelectric film <NUM> around a core yarn <NUM>. The piezoelectric film <NUM> is an example of the "piezoelectric body" in the present invention. The core yarn <NUM> is appropriately selected from cotton, silk, general synthetic fiber, or the like. The core yarn <NUM> may be a conductive yarn having electrical conductivity. In the case of using a conductive yarn as the core yarn <NUM>, when the piezoelectric properties of the piezoelectric yarn are checked, an electric charge generated on the piezoelectric yarn <NUM> (or piezoelectric yarn <NUM>) can be measured using an electrode formed on a part of the outer region of the piezoelectric yarn <NUM> (or piezoelectric yarn <NUM>) and the core yarn <NUM>. This allows the piezoelectric performance of the piezoelectric film <NUM> that is used on the piezoelectric yarns <NUM> and <NUM> to be checked. Further, the conductive yarns are short-circuited to each other to thereby clearly form a circuit among the yarns, so that an electric field generated between the surfaces of the yarns is remarkably increased. The piezoelectric film <NUM> is made of, for example, uniaxially stretched polylactic acid.

<FIG> is a view showing the piezoelectric yarn <NUM> when an external force is applied, and <FIG> is a view showing the piezoelectric yarn <NUM> when an external force is applied.

As shown in <FIG>, the piezoelectric yarn <NUM> is a left-twisted yarn (hereinafter referred to as S yarn) in which the piezoelectric film <NUM> is twisted around the core yarn <NUM> to the left. The stretching direction <NUM> is tilted at <NUM> degrees leftward with respect to the axial direction of the piezoelectric yarn <NUM>. Therefore, as shown in <FIG>, when an external force is applied to the piezoelectric yarn <NUM>, the piezoelectric film <NUM> becomes in the state as shown in <FIG>, which in turn generates a negative electric charge on its surface. Thus, the piezoelectric yarn <NUM> generates a negative electric charge on its surface when an external force is applied.

Further, as shown in <FIG>, the piezoelectric yarn <NUM> is a right-twisted yarn (hereinafter referred to as Z yarn) in which the piezoelectric film <NUM> is twisted around the core yarn <NUM> to the right. The stretching direction <NUM> is tilted at <NUM> degrees rightward with respect to the axial direction of the piezoelectric yarn <NUM>. Therefore, as shown in <FIG>, when an external force is applied to the piezoelectric yarn <NUM>, the piezoelectric film <NUM> becomes in the state as shown in <FIG>, which in turn generates a positive electric charge on its surface. Thus, the piezoelectric yarn <NUM> generates a positive electric charge on its surface when an external force is applied.

<FIG> is an outline view of a cushion <NUM> including the nonwoven member <NUM>. The nonwoven member <NUM> is filled in the cushion <NUM>.

Since the nonwoven member <NUM> produces an electric field by a piezoelectric effect, no power supply is required, and an electric shock may not occur. The life of the piezoelectric body lasts longer than the antibacterial effect of chemicals or the like. Further, the piezoelectric body may cause an allergic reaction less than chemicals. The nonwoven member <NUM> accidentally forms a circuit with the piezoelectric yarns <NUM> and <NUM> that form the nonwoven member itself, by intertwining these yarns, to thereby solely produce an electric field, or forms a current path in the presence of humidity to thereby flow an electric current. This exerts an antibacterial action and an antifungal action on the bacteria that migrate to the cushion <NUM> (nonwoven member <NUM>). In particular, a cushion is inevitably stretched due to the movement such as reclining. Therefore, the nonwoven member <NUM> filled in the cushion generates an electric charge at a high frequency. In addition, the cushion absorbs moisture such as perspiration or the like to become a hotbed for growth of bacteria. The nonwoven member <NUM> is, however, capable of inhibiting the growth of bacteria (germs, fungi, etc.) and thus produces a remarkable effect as applications for antibacterial measure and measure against odor.

In the present embodiment, the piezoelectric film is shown as an example of the piezoelectric body. The piezoelectric body may, however, be a yarn discharged from a nozzle and then stretched (a piezoelectric yarn having a generally circular cross section or a piezoelectric yarn having a modified cross section). For example, a polylactic acid (PLLA) piezoelectric yarn may be prepared by melt spinning, high stretching, or heat treatment (for crystallization). Such a yarn (multifilament yarn) obtained by twisting a plurality of PLLA piezoelectric yarns may be formed. Even when a tension is applied to the multifilament yarn, the S yarn generates a negative electric charge on its surface and the Z yarn generates a positive electric charge on its surface. These yarns can be simply twisted without using a core yarn. The thus twisted yarn can be manufactured at a low cost. The number of filaments of the multifilament yarn is set in view of the uses of the yarn. The number of twists is also appropriately set. A filament which is not partially a piezoelectric body may be contained in the plurality of filaments. The thickness of the filaments may not be uniform. When the plurality of filaments do not have a uniform thickness, a potential distribution produced in the cross section of the yarn deviates to break symmetry. Therefore, an electric field circuit between the S yarn and the Z yarn is readily formed.

Although the present embodiment exemplifies a yarn obtained by twisting the piezoelectric film <NUM> around the core yarn <NUM>, the core yarn <NUM> is not always required for both the S yarn and the Z yarn. Without the core yarn <NUM>, it is possible to helically twist the piezoelectric film <NUM> to produce a piezoelectric yarn (twisted yarn). In the absence of the core yarn <NUM>, the twisted yarn becomes hollow to improve heat retaining performance. Further, it is possible to increase the strength of the twisted yarn by impregnating the twisted yarn itself with an adhesive.

The piezoelectric yarn may be a yarn which generates an electric charge when an energy is applied thereto, and, for example, the above-mentioned PVDF or the like may be useful. The piezoelectric body having pyroelectricity such as PVDF generates an electric charge on its surface due to heat energy on a body surface of an animal. Thus, the piezoelectric body having pyroelectricity such as PVDF exerts an antibacterial effect. In the case of using PVDF, the piezoelectric body exerts an antibacterial effect without stretching the yarn as long as ambient temperature or body temperature changes. That is, the piezoelectric yarn of the present invention may be any piezoelectric body as long as the piezoelectric body generates an electric charge not only when the yarn is stretched but also when an external force is applied thereto.

The mixing ratio of the S yarn to the Z yarn may be <NUM> : <NUM>, and even though the ratio is out of this, the effect as described above can be obtained. To the extent that a substance attraction effect is exerted, the nonwoven member may be made of either the S yarn or the Z yarn.

Further, any well-known method may be adopted as a method of manufacturing the piezoelectric yarn. The method that may be used includes, for example, a method of extruding a piezoelectric polymer to form a fiber; a method of melt-spinning a piezoelectric polymer to form a fiber; a method of dry-spinning or wet-spinning a piezoelectric polymer to form a fiber; a method of electrostatic spinning a piezoelectric polymer to form a fiber; or the like.

The second embodiment shows an example of the nonwoven member as a pellet for packaging materials.

<FIG> is an outline view of a nonwoven member <NUM> according to a second embodiment, and <FIG> is an enlarged view of a mass <NUM> included in the nonwoven member <NUM>.

The nonwoven member <NUM> includes a mass <NUM> containing a piezoelectric body. The mass <NUM> is composed of a piezoelectric yarn <NUM> and a piezoelectric yarn <NUM>, and a foam <NUM>. As shown in <FIG>, the mass <NUM> is a cushioning material in which the piezoelectric yarns <NUM> and <NUM> are cut into short lengths and the short pieces are mixed with the foam <NUM>. The piezoelectric yarns <NUM> and <NUM> are the same as those described in the first embodiment. The foam <NUM> is, for example, foamed polypropylene. The nonwoven member <NUM> according to this embodiment is, for example, a buffer material (pellet) for packaging materials.

The nonwoven member <NUM> solely produces an electric field with the piezoelectric yarns <NUM> and <NUM> that form the nonwoven member itself. This exerts an antibacterial action and an antifungal action on the bacteria that migrate to the nonwoven member <NUM>. In particular, the buffer material for packaging materials is inevitably stretched due to the movement of articles to be protected during traveling. Therefore, the nonwoven member <NUM> generates an electric charge at a high frequency. Therefore, it produces a remarkable effect as applications for antibacterial measure and antifungal measure.

The second comparative example shows a different example of the buffer material (nonwoven member) shown in the second embodiment.

<FIG> is an outline view of a nonwoven member <NUM> according to second comparative example. <FIG> is a plan schematic view of a cloth <NUM> included in the nonwoven member <NUM>, and <FIG> is a view showing electric fields generated between the yarns when an external force is applied to the cloth <NUM>.

The nonwoven member <NUM> includes a mass <NUM> containing a piezoelectric body. The nonwoven member <NUM> according to this example is, for example, a buffer material (pellet) for packaging materials.

The mass <NUM> is obtained by rounding the cloth <NUM> shown in <FIG> into a ball shape. The cloth <NUM> is woven of the piezoelectric yarn <NUM> made from a piezoelectric body, the piezoelectric yarn <NUM> made from a piezoelectric body, and an ordinary yarn <NUM>. The ordinary yarn <NUM> is a yarn which is not provided with a piezoelectric body and is equivalent to a dielectric. The piezoelectric yarns <NUM> and <NUM> are the same as those described in the first embodiment.

As shown in <FIG>, the piezoelectric yarn <NUM>, the piezoelectric yarn <NUM>, and the ordinary yarn <NUM> are arranged in parallel. Each of the piezoelectric yarns <NUM> and <NUM> is arranged at a predetermined spaced interval with the ordinary yarn <NUM>, which is equivalent to a dielectric, being interposed between the piezoelectric yarns.

The piezoelectric yarn <NUM> (S yarn) generates a negative electric charge on its surface when an external force is applied (when pulled in the axial direction). The piezoelectric yarn <NUM> (Z yarn) generates a positive electric charge on its surface when an external force is applied (when pulled in the axial direction). When the piezoelectric yarns <NUM> and <NUM> come close to each other, the close portions (surfaces of the piezoelectric yarns) tend to have the same potential. On the other hand, portions equivalent to cores of the piezoelectric yarns show a potential that opposes that on the surfaces of the piezoelectric yarns, while maintaining the original potential difference. Therefore, an electric field directed from the core of the yarn to the outside of the yarn is formed in proximity (surrounding space) to the piezoelectric yarn <NUM>, and an electric field directed from the outside of the yarn to the core of the yarn is formed in proximity (surrounding space) of the piezoelectric yarn <NUM>. As a result of combining these electric fields, an electric field directed from the piezoelectric yarn <NUM> to the piezoelectric yarn <NUM> is formed between the piezoelectric yarns <NUM> and <NUM>.

The piezoelectric yarn <NUM>, the piezoelectric yarn <NUM>, and the ordinary yarn <NUM> are arranged very close to each other, with almost no distance therebetween. These yarns are complicatedly intertwined to form a circuit at a local portion, and an electric field is produced between the yarns by a piezoelectric effect. The strength of the electric field increases in inversely proportion to the distance between substances which generate an electric charge as represented as E = V/d. The strength of the electric field produced by the cloth <NUM> thus results in a very large value. Such an electric field is formed by mutually combining the electric field generated inside and outside the piezoelectric yarn <NUM> with the electric field generated inside and outside the piezoelectric yarn <NUM>. In some circumstances, a circuit may be formed as an actual current path due to moisture containing an electrolyte such as perspiration. In a fiber knitted cloth, fibers are complicatedly intertwined, so that an electric field generated in one portion of the piezoelectric yarn <NUM> and an electric field generated in the other portion thereof may be mutually combined. Similarly, an electric field generated in one portion of the piezoelectric yarn <NUM> and an electric field generated in the other portion thereof may be mutually combined. Even in the case where the strength of the electric field is macroscopically none or very weak, strong electric fields having conflicting vector directions may be microscopically assembled. These phenomena may be similarly described with a cloth formed of the piezoelectric yarn <NUM> alone, a cloth formed of the piezoelectric yarn <NUM> alone, or a cloth in which an ordinary yarn or a conductive yarn is knitted together with these clothes.

It should be noted that an electric field is not formed in the following example. <CIT> discloses a transducer which senses a displacement applied to a knitted or woven fabric using a plurality of piezoelectric yarns and conductive yarns. In the transducer, all the conductive yarns are connected to a detection circuit and a conductive yarn always pairs with a piezoelectric yarn. When an electric charge is generated in the piezoelectric yarn, an electron migrates from the conductive yarn to immediately neutralize the generated electric charge. In the transducer, the detection circuit detects an electric current generated due to the migration of the electron and then outputs as a signal. Accordingly, the transducer immediately cancels the generated potential, so that no strong electric field is formed between the piezoelectric yarn and the conductive yarn, and the piezoelectric yarn and the piezoelectric yarn.

As described above, conventionally, there has been known that an electric field can inhibit the growth of bacteria. It is, therefore, considered that the cloth <NUM> exerts an antibacterial effect by the electric field generated by itself and variation in its strength. Alternatively, the cloth <NUM> exerts an antibacterial or sterilizing effect by radical species generated by the action of the electric current or voltage. The cloth <NUM> solely produces an electric field with the piezoelectric yarns <NUM> and <NUM> that form the cloth itself. This exerts an antibacterial action and an antifungal action on the bacteria that migrate to the nonwoven member <NUM>.

As described above, the piezoelectric yarn <NUM> generates a negative electric charge when an external force is applied. The piezoelectric yarn <NUM> generates a positive electric charge when an external force is applied. Therefore, the piezoelectric yarn <NUM> attracts a substance having a positive electric charge (e.g., particles such as pollen) and the piezoelectric yarn <NUM> attracts a substance having a negative electric charge (e.g., harmful substances such as yellow dust). Accordingly, it is possible for the cloth <NUM> including the piezoelectric yarn <NUM> or <NUM> to attract fine particles such as pollen or yellow dust.

<FIG> is a plan schematic view of another cloth 100A according to the second comparative example, and <FIG> is a view showing electric fields between the yarns.

As shown in <FIG>, the cloth 100A has the piezoelectric yarn <NUM>, the piezoelectric yarn <NUM>, and the ordinary yarn <NUM> arranged in crossed relation. Even such a configuration is likely to generate an electric field at a location where the piezoelectric yarns <NUM> and <NUM> are crossed.

The example exemplifies that the mass <NUM> is obtained by rounding the cloth <NUM> into a ball shape. However, the mass may be, for example, a piece of cloth obtained by simply cutting the cloth <NUM> into small pieces and not necessarily have a ball shape.

The example exemplifies that the mass <NUM> is formed of the cloth <NUM>. In an embodiment of the invention, the cloth which forms the mass may be a nonwoven fabric in which piezoelectric fibers are not woven but intertwined into a sheet.

Most of the bacteria have a negative electric charge. For this reason, the piezoelectric yarn <NUM> allows most of the bacteria to attract with the positive electric charge generated when an external force is applied. Also, it is possible to inactivate bacteria having a negative electric charge by using a cloth woven of the piezoelectric yarn <NUM> in the mass.

The present example exemplifies the case where the cloth <NUM> is formed by combining the S yarn and the Z yarn both made of the same polylactic acid (e.g., PLLA). The same effect is, however, exerted, for example, when an S yarn made of PLLA and an S yarn made of PDLA are combined. In addition, even when a Z yarn made of PLLA and a Z yarn made of PDLA are combined, the same effect is exerted.

The third embodiment shows an example of the buffer material different from those in the first and second embodiments.

<FIG> is an outline view of a nonwoven member <NUM> according to a third embodiment.

<FIG> is an outline view of the piezoelectric yarn <NUM> which forms a mass 25A and <FIG> is an outline view of the piezoelectric yarn <NUM> which forms a mass 25B.

The nonwoven member <NUM> includes masses 25A and 25B each containing a piezoelectric body. The nonwoven member <NUM> according to the present embodiment is, for example, a buffer material (pellet) for packaging materials.

The mass 25A is obtained by rounding the piezoelectric yarn <NUM> shown in <FIG> into a ball shape. The mass 25B is obtained by rounding the piezoelectric yarn <NUM> shown in <FIG> into a ball shape. The piezoelectric yarns <NUM> and <NUM> are the same as those described in the first embodiment.

The piezoelectric yarn <NUM> generates a negative electric charge on its surface when an external force is applied (when pulled in the axial direction). The piezoelectric yarn <NUM> generates a positive electric charge on its surface when an external force is applied (when pulled in the axial direction). Therefore, when an external force is applied to these yarns, an electric field is produced between the mass 25B (piezoelectric yarn <NUM>) that generates a positive electric charge and the mass 25A (piezoelectric yarn <NUM>) that generates a negative electric charge. As described above, the electric fields in the portions where the piezoelectric yarns <NUM> and <NUM> are close to each other tend to have the same potential, and an electric field from the piezoelectric yarn <NUM> to the piezoelectric yarn <NUM> is primarily formed. That is, the nonwoven member <NUM> produces an electric field with the masses 25A (piezoelectric yarn <NUM>) and 25B (piezoelectric yarn <NUM>) that form the nonwoven member itself. This exerts an antibacterial action and an antifungal action on the bacteria that migrate to the nonwoven member <NUM>.

The present embodiment exemplifies the nonwoven member <NUM> including the masses 25A and 25B that round piezoelectric yarns <NUM> and <NUM>, respectively, into a ball shape. However, the present invention is not limited to this configuration. For example, the mass of the present invention may have a ball shape formed by intertwining the piezoelectric yarns <NUM> and <NUM> each other. The nonwoven member may also be a lint obtained by simply cutting the piezoelectric yarns <NUM> and <NUM> into short lengths, and not necessarily have a ball shape. Further, the nonwoven member may be a mixture of the lint obtained by simply cutting the piezoelectric yarns <NUM> and <NUM> into short lengths with the piece of cloth obtained by simply cutting the cloth <NUM> into small pieces as shown in the third embodiment.

The third comparative example shows an example of the nonwoven member in which the shape of the mass is different from those in the preceding embodiments.

<FIG> is an outline view of a nonwoven member <NUM> according to a third comparative example and <FIG> is an enlarged view of a DP2 portion shown in <FIG>.

The nonwoven member <NUM> includes a mass <NUM> containing a piezoelectric body. The mass <NUM> is composed of a piezoelectric fiber <NUM> and a resin fiber <NUM>. As shown in <FIG>, the mass <NUM> is a buffer material obtained by intertwining the piezoelectric fiber <NUM> and the resin fiber <NUM> each other and solidifying them. The piezoelectric fiber <NUM> is the same as the one described in the first comparative example. The resin fiber <NUM> is, for example, a polyester fiber. The nonwoven member <NUM> according to this example is, for example, a mattress material for bed.

The nonwoven member <NUM> produces an electric field between the nonwoven member and a human body due to the piezoelectric fiber <NUM> that forms the nonwoven member itself when an external force is applied. This exerts an antibacterial action and an antifungal action on the bacteria that migrate to the nonwoven member <NUM>. In particular, the mattress for bed is inevitably stretched due to the movement of a human body during sleeping. Therefore, the piezoelectric fiber <NUM> generates an electric charge at a high frequency. In addition, the mattress for bed comes in contact with moisture such as perspiration or the like to become a hotbed for growth of bacteria. The nonwoven member <NUM> is, however, capable of inhibiting the growth of bacteria and thus produces a remarkable effect as applications for antibacterial measure, antifungal measure, and measure against odor.

When a human lies on a bed including the above-mentioned mattress, the nonwoven member <NUM> is positioned close to a human skin, so that an electric field is generated between the human skin and the nonwoven member <NUM> due to application of an external force to the nonwoven member <NUM>. Therefore, since an electric field is generated between the human skin and the nonwoven member <NUM> in the case where a human lies on the bed, an antibacterial effect and a mildewproofing effect are also exerted on an object (e.g., sheets, etc.) positioned between the human and the nonwoven member <NUM>.

The present example exemplifies the mass formed by intertwining the piezoelectric fiber and the resin fiber and solidifying them. However, the mass is not limited to this configuration. The mass may be formed by intertwining a piezoelectric yarn and a resin fiber and solidifying them. The mass may be formed by mixing a piezoelectric fiber (or piezoelectric yarn) with a foam.

The fourth embodiment shows a different example of the yarns shown in the preceding embodiments.

<FIG> is a partially exploded view showing a configuration of a piezoelectric yarn <NUM> and <FIG> is a partially exploded view showing a configuration of a piezoelectric yarn <NUM>.

The piezoelectric yarn <NUM> is obtained by further winding the piezoelectric film <NUM> on a piezoelectric covering yarn 1A, which is an S yarn. The piezoelectric yarn <NUM> is obtained by further winding the piezoelectric film <NUM> on a piezoelectric covering yarn 2A, which is a Z yarn.

As shown in <FIG>, the piezoelectric yarn <NUM> is a left-twisted yarn (S yarn) in which the piezoelectric film <NUM> is twisted to the left to cover the piezoelectric covering yarn 1A. The stretching direction <NUM> is tilted at <NUM> degrees leftward with respect to the axial direction of the piezoelectric yarn <NUM>. The stretching direction <NUM> is in line with a stretching direction 900A of the piezoelectric covering yarn 1A.

When the piezoelectric yarn <NUM> is pulled in the axial direction (when an external force is applied), a negative electric charge is generated on the surface of the piezoelectric covering yarn 1A. On the other hand, a positive electric charge is generated on the rear surface of the piezoelectric film <NUM> that is opposed to the surface of the piezoelectric covering yarn 1A. When the surface of the piezoelectric covering yarn 1A and the rear surface of the piezoelectric film <NUM> are completely in contact with each other, the contact portions have the same potential. However, when a potential difference is defined in a clearance accidentally generated due to stretching of the yarn or the like, an electric field is produced in the clearance. The potential difference at each point is defined by an electric field coupling circuit formed by complicatedly intertwining yarns, or a circuit formed by a current path which is accidentally formed in the yarn due to moisture or the like. When the circuit is formed, the strength of the electric field increases in inversely proportion to the distance between substances which generate electric charges. Therefore, the strength of the electric field produced between the surface of the piezoelectric covering yarn 1A and the rear surface of the piezoelectric film <NUM> may be extremely increased. That is, this configuration further enhances an antibacterial effect or a sterilizing effect of the yarn itself. When the piezoelectric yarn <NUM> is pulled in the axial direction (when an external force is applied), a negative electric charge is generated on the surface of the piezoelectric yarn <NUM> (the surface of the piezoelectric film <NUM>). Therefore, it is possible to further generate an electric field between the yarns by combining the piezoelectric yarn <NUM> with a yarn of which a positive electric charge is generated on its surface (the piezoelectric yarn <NUM> to be described later).

As shown in <FIG>, the piezoelectric yarn <NUM> is a right-twisted yarn (Z yarn) in which the piezoelectric film <NUM> is twisted to the right to cover the piezoelectric covering yarn 2A. The stretching direction <NUM> is tilted at <NUM> degrees rightward with respect to the axial direction of the piezoelectric yarn <NUM>. The stretching direction <NUM> is in line with the stretching direction 900A of the piezoelectric covering yarn 2A.

When the piezoelectric yarn <NUM> is pulled in the axial direction (when an external force is applied), a positive electric charge is generated on the surface of the piezoelectric covering yarn 2A (the surface of the piezoelectric film <NUM>). On the other hand, a negative electric charge is generated on the rear surface of the piezoelectric film <NUM> that is opposed to the surface of the piezoelectric covering yarn 2A. When the surface of the piezoelectric covering yarn 2A and the rear surface of the piezoelectric film <NUM> are completely in contact with each other, the contact portions have the same potential. However, when a potential difference is defined in a clearance accidentally generated due to stretching of the yarn or the like, an electric field is produced in the clearance. The potential difference at each point is defined by an electric field coupling circuit formed by complicatedly intertwining yarns, or a circuit formed by a current path which is accidentally formed in the yarn due to moisture or the like. When the circuit is formed, the strength of the electric field increases in inversely proportion to the distance between substances which generate electric charges. Therefore, the strength of the electric field produced between the surface of the piezoelectric covering yarn 2A and the rear surface of the piezoelectric film <NUM> may be extremely increased. That is, as in the case with the piezoelectric yarn <NUM>, this configuration further enhances an antibacterial effect or a sterilizing effect of the yarn itself. When the piezoelectric yarn <NUM> is pulled in the axial direction (when an external force is applied), a positive electric charge is generated on the surface of the piezoelectric yarn <NUM> (the surface of the piezoelectric film <NUM>). Therefore, it is possible to generate an electric field between the yarns by combining the piezoelectric yarn <NUM> with a yarn of which a negative electric charge is generated on its surface like the piezoelectric yarn <NUM>.

The yarn may have the following configuration. <FIG> is a partially exploded view showing a configuration of a piezoelectric yarn <NUM> and <FIG> is a partially exploded view showing a configuration of a piezoelectric yarn <NUM>.

The piezoelectric yarn <NUM> is obtained by winding the piezoelectric film <NUM> on the piezoelectric covering yarn 1A. The piezoelectric yarn <NUM> is obtained by winding the piezoelectric film <NUM> around the piezoelectric covering yarn 2A.

As shown in <FIG>, the piezoelectric yarn <NUM> is a right-twisted yarn (Z yarn) in which the piezoelectric film <NUM> is twisted to the right to cover the piezoelectric covering yarn 1A. The stretching direction <NUM> is tilted at <NUM> degrees rightward with respect to the axial direction of the piezoelectric yarn <NUM>. The stretching direction <NUM> is different from the stretching direction 900A of the piezoelectric covering yarn 1A.

As shown in <FIG>, the piezoelectric yarn <NUM> is a left-twisted yarn (S yarn) in which the piezoelectric film <NUM> is twisted to the left to cover the piezoelectric covering yarn 2A. The stretching direction <NUM> is tilted at <NUM> degrees leftward with respect to the axial direction of the piezoelectric yarn <NUM>. The stretching direction <NUM> is different from the stretching direction 900A of the piezoelectric covering yarn 2A.

<FIG> is an exaggerated view showing clearances of the piezoelectric film <NUM> in the piezoelectric yarn <NUM>. The piezoelectric yarn <NUM> generates a certain degree of clearance D in the case of winding the piezoelectric film <NUM> around the covering yarn. The clearance D produces an electric field between the surface of the piezoelectric covering yarn 1A and the surface of the piezoelectric film <NUM> when the piezoelectric yarn <NUM> is pulled in the axial direction. Thus, this configuration further enhances an antibacterial effect or an antifungal effect of the yarn itself. The same applies to the piezoelectric yarn <NUM>.

In the piezoelectric yarn <NUM>, when PDLA is used in either the piezoelectric covering yarn 1A or the piezoelectric film <NUM>, the electric charge generated on the surface of the piezoelectric covering yarn 1A and the electric charge generated on the rear surface of the piezoelectric film <NUM> have different polarities, so that the piezoelectric yarn <NUM> is formed in the same manner as the piezoelectric yarn <NUM>, thereby producing a strong electric field between the surface of the piezoelectric covering yarn 1A and the rear surface of the piezoelectric film <NUM>. The same applies to the piezoelectric yarn <NUM> when PDLA is used in either the piezoelectric covering yarn 2A or the piezoelectric film <NUM>.

Further, the yarn may have the following configuration. <FIG> is a partially exploded view showing a configuration of a piezoelectric yarn <NUM>.

The piezoelectric yarn <NUM> is a yarn (S yarn) in which the piezoelectric yarns <NUM> and <NUM> are twisted around each other to the left. Since the piezoelectric yarn <NUM> is formed by intersecting the piezoelectric yarn <NUM> that generates a negative electric charge on its surface with the piezoelectric yarn <NUM> that generates a positive electric charge on its surface, the yarn can solely produce an electric field. As described above, the potentials generated on the respective surfaces of the piezoelectric yarns <NUM> and <NUM> tend to become equal at the portions where the surfaces of the piezoelectric yarns <NUM> and <NUM> are close to each other. Accordingly, the potential in the yarn varies to try to keep a potential difference between the surface and the inside of the yarn. Regarding the yarns, electric fields formed between the inside and the surface of the yarn are leaked out into air and then combined to form a strong electric field in the portions where the piezoelectric yarns <NUM> and <NUM> are close to each other. The twisted yarn has a complicated structure and is not uniform at the portions where the piezoelectric yarns <NUM> and <NUM> are close to each other. Further, when a tension is applied to the piezoelectric yarns <NUM> and <NUM>, such close portions thereof also vary. Thus, the strength of the electric field at each of the portions varies, which in turn generates an electric field circuit where its symmetry is broken. Since a yarn (Z yarn) in which the piezoelectric yarns <NUM> and <NUM> are twisted around each other to the right is also formed by intersecting the piezoelectric yarn <NUM> that generates a negative electric charge on its surface with the piezoelectric yarn <NUM> that generates a positive electric charge on its surface, the yarn can solely produce an electric field. The number of twists in the piezoelectric yarn <NUM> and the number of twists in the piezoelectric yarn <NUM>, or the number of twists in the piezoelectric yarn <NUM> made by twisting these yarns is determined in view of the antibacterial effect. All the preceding applications can be formed using the piezoelectric yarn <NUM>. Since a yarn (Z yarn) in which the piezoelectric yarns <NUM> and <NUM> are twisted around each other to the right is also formed by intersecting the piezoelectric yarn <NUM> that generates a negative electric charge on its surface with the piezoelectric yarn <NUM> that generates a positive electric charge on its surface, the yarn can solely produce an electric field.

In addition to this, even a triple-covering yarn in which an ordinary yarn is twisted on the side surface of the S yarn (or Z yarn) and the Z yarn (or S yarn) is further twisted on its side surface can solely produce an electric field.

The yarn may be a yarn (third yarn) made of a braid which simultaneously forms the piezoelectric yarn <NUM> twisted to the right and the piezoelectric yarn <NUM> twisted to the left around the surface of the ordinary yarn, like the piezoelectric yarn <NUM> shown in <FIG> is a view showing a configuration of a piezoelectric yarn <NUM>. As shown in <FIG>, even such a configuration produces an electric field at a position where the piezoelectric yarns <NUM> and <NUM> are crossed, so that the yarn can solely produce an electric field.

As the yarn that generates a negative electric charge on its surface, a Z yarn using PDLA as well as an S yarn using PLLA is considered. In addition, as the yarn that generates a positive electric charge on its surface, an S yarn using PDLA as well as a Z yarn using PLLA is considered. Therefore, for example, in the configuration shown in <FIG>, a piezoelectric yarn made of a yarn (S yarn) obtained by twisting the S yarn using PLLA and the Z yarn using PDLA around each other to the left, or a yarn (Z yarn) obtained by twisting those yarns to the right can solely produce an electric field.

Next, the antibacterial effect of the yarn made from a piezoelectric body will be described. The inventors of the present invention performed quantitative tests shown in the following (<NUM>) and (<NUM>) in order to evaluate the bacteria inhibitory effect of the cloth woven of yarns made from a piezoelectric body.

(<NUM>) Evaluation of Antibacterial Properties of a Cloth Woven of Yarns Made from a Piezoelectric Body.

It can be clearly seen from TABLE <NUM> that the test sample (cloth woven of yarns made from a piezoelectric body) has a higher antibacterial action on germs than the standard cloth. As compared to the state where the test sample is allowed to stand, the vibrated test sample has a higher antibacterial action. In particular, in the case where the test sample is vibrated to generate an electric field, little viable cells are observed <NUM> hours after inoculation of test bacteria (germs) and a high antibacterial action is exerted.

(<NUM>) Evaluation of Antifungal Properties of a Cloth Woven of Yarns Made from a Piezoelectric Body.

a) Test method: Antifungal quantitative test method (procedure specified by Japan Textile Evaluation Technology Council (JTETC)
b) Test bacteria: Aspergillus niger NBRC105649
c) Inoculum concentration: <NUM> × <NUM><NUM> (CFU/mL)
d) Standard cloth: Cloth woven of cotton yarns and cloth knitted from cotton yarns
e) Test sample (antibacterial-finished sample) Cloth knitted from S yarn (piezoelectric yarn <NUM>) obtained by twisting an S yarn (piezoelectric yarn <NUM>) and a Z yarn (piezoelectric yarn <NUM>) around each other to the left
[Calculating Formula].

• Development value: F = Fb - Fa
• Antifungal activity value: FS = (Fb - Fa) - (Fc - Fo)
• Fa: The arithmetical mean common logarithm for the viable cell count (or ATP amount) obtained from three test samples of the standard cloth immediately after inoculation of test bacteria
• Fb: The arithmetical mean common logarithm for the viable cell count (or ATP amount) obtained from three test samples of the standard cloth after <NUM>-hour cultivation
• Fo: The arithmetical mean common logarithm for the viable cell count (or ATP amount) obtained from three test samples (antibacterial-finished samples) immediately after inoculation of test bacteria
• Fc: The arithmetical mean common logarithm for the viable cell count (or ATP amount) obtained from three test samples (antibacterial-finished samples) after <NUM>-hour cultivation.

It can be clearly seen from TABLE <NUM> that the test sample (cloth woven of yarns made from a piezoelectric body) has a higher antibacterial action on fungi (mold, etc.) than the standard cloth. As compared to the state where the test sample is allowed to stand, the vibrated test sample has a higher antifungal action. That is, the test sample exerts a high antifungal action when vibrated to produce an electric field.

The above results revealed that the cloth <NUM> woven of yarns made from a piezoelectric body has antibacterial properties and antifungal properties.

Claim 1:
An antibacterial nonwoven member (<NUM>, <NUM>, <NUM>)
comprising a nonwoven mass (<NUM>, <NUM>, <NUM>, <NUM>) containing a piezoelectric body (<NUM>), the piezoelectric body having a first piezoelectric body and a second piezoelectric body; and
a plurality of yarns having a first yarn (<NUM>) made from the first piezoelectric body (<NUM>) and a second yarn (<NUM>) made from the second piezoelectric body (<NUM>);
the first yarn generating a positive electric charge when an external force is applied and
the second yarn generating a negative electric charge when an external force is applied,
wherein the antibacterial nonwoven member inhibits growth of bacteria due to an electric charge generated when an external force is applied to the piezoelectric body.