Background of the Invention
1. Field of the Invention
[0001] The present invention relates to a yarn, more specifically, a yarn capable of forming
an electric field by surface charge, more specifically, capable of generating a potential.
The present invention also relates to a fabric, more specifically, a fabric containing
the above-mentioned yarn.
2. Description of the Related Art
Summary of the Invention
[0003] The present inventors have found that conventional fibrous materials having antibacterial
properties have problems to overcome, and have found that there is a need to make
improvements thereon.
Specifically, the present inventors have found that there are the following problems.
[0004] As a conventional fibrous material having antibacterial properties, in particular,
an antibacterial yarn containing a plurality of charge-generating fibers that generate
charges by external energy, e.g., external force such as tension is known (for example,
JP-B2-6428979). Such an antibacterial yarn is characterized in that the state of spaces between
the plurality of charge-generating fibers is not uniform, and thereby the antibacterial
yarn exhibits antibacterial properties by generating a bias in electrical characteristics
and forming a locally strong electric field.
[0005] However, according to the research by the present inventors, it has been found that
the electric field that can be formed has a decreased electric field intensity depending
on the state of spaces between charge-generating fibers, especially the physical properties
such as permittivity of the dielectric existing between the charge-generating fibers,
and antibacterial properties may not be obtained. In addition, physical property values
from which antibacterial properties can be easily confirmed were also unknown.
[0006] The present invention has been devised in view of such problems, and a main object
of the present invention is to find a physical property value with which antibacterial
properties can be more reliably obtained and provide a yarn capable of being used
as an antibacterial yarn. It is also an object of the present invention to provide
a fabric containing the above-mentioned yarn.
[0007] As a result of intensive research, the present inventors have focused on a permittivity,
especially a "specific permittivity", as physical properties of a yarn containing
charge-generating fibers (in other words, fibers or filaments capable of generating
a potential and forming an electrical field by generating charges (hereinafter, referred
to as a "potential-generating filament" or an "electric field-forming filament") as
described in more detail below), and they have found that when the value of the permittivity
is "about 4.5 or less", antibacterial properties are more reliably obtained and the
yarn can be successfully used as an antibacterial yarn. As a result, the present inventors
have accomplished the invention of a yarn that has achieved the main object described
above.
[0008] The present invention provides a yarn comprising a potential-generating filament,
wherein the yarn has a specific permittivity of about 4.5 or less. The present invention
also provides a fabric comprising the yarn.
[0009] According to the present invention, it is possible to provide products such as a
yarn capable of more reliably exhibiting antibacterial properties (more preferably,
an antibacterial yarn), and a fabric containing such a yarn (more preferably, an antibacterial
fabric).
Brief Description of the Drawings
[0010]
Fig. 1(A) is a diagram illustrating the configuration of a yarn 1 (S yarn), Fig. 1(B)
is a cross-sectional view taken along line A-A of Fig. 1(A), and Fig. 1(C) is a cross-sectional
view taken along line B-B of Fig. 1(A);
Figs. 2(A) and 2(B) are diagrams showing a relationship among a uniaxial drawing direction
of polylactic acid, an electric field direction, and deformation of a potential-generating
filament (or piezoelectric fiber) 10;
Fig. 3(A) is a diagram illustrating the configuration of a yarn 2 (Z yarn), Fig. 3(B)
is a cross-sectional view taken along line A-A of Fig. 3(A), and Fig. 3(C) is a cross-sectional
view taken along line B-B of Fig. 3(A);
Fig. 4 is a cross-sectional view schematically illustrating a cross section of a yarn
of the present disclosure having a dielectric 100 around the potential-generating
filament 10;
Fig. 5 is a graph showing a relationship between a specific permittivity (ε) of a
dielectric and an electric field intensity (V/µm);
Fig. 6 is a schematic view briefly illustrating a method of measuring the impedance
of a yarn of the present disclosure using an LCR meter;
Fig. 7 is a graph showing a relationship between an interval d (µm) between potential-generating
filaments and an electric field intensity (V/µm);
Fig. 8 shows a result of a preliminary test for confirming an antibacterial action
by electrical stimulation;
Fig. 9(a) is a photograph showing the state of Trichophyton before and after voltage
application for a sample of 20 V × 5 Hz in the table of Fig. 8, and Fig. 9(b) is a
photograph showing a sample of 50 V × 5 Hz in the table of Fig. 8;
Fig. 10 is a photograph showing the Trichophyton used in the preliminary test;
Fig. 11 is a schematic view schematically illustrating a method of preparing a yarn
bundle sample;
Fig. 12 is a photograph illustrating one example of a method of measuring the specific
permittivity of a yarn with a yarn bundle sample; and
Fig. 13 is a schematic view schematically illustrating a method of measuring the specific
permittivity of a yarn in a yarn bundle sample.
Detailed Description of the Invention
[0011] Hereinafter, a yarn according to one embodiment of the present invention (hereinafter,
sometimes briefly referred to as "yarn of the present disclosure" or simply "yarn")
will be described in detail. Although the description will be made with reference
to the drawings as necessary, elements in the drawings are merely schematically and
exemplarily shown for understanding of the present invention, and appearance, dimensional
ratios, and the like may differ from actual ones.
[0012] The yarn of the present disclosure contains a "potential-generating filament", and
is characterized in that the "specific permittivity" as a physical property thereof
is "about 4.5 or less". With such a configuration and characteristic, the yarn of
the present disclosure can more reliably exhibit "antibacterial property" described
in detail below, and can be used as an "antibacterial yarn".
[0013] The numerical ranges referred to herein are intended to include the lower and/or
upper numerical limits themselves, unless otherwise noted, such as "less than" or
"more than/greater than". That is, taking the numerical range of 1 to 10 as an example,
it can be interpreted as including the lower limit value "1" and the upper limit value
"10".
[0014] In addition, some numerical values may be attached with "about", and the term "about"
means that the numerical values may include variations of several percent, for example,
± 9%, ± 4%, ± 2%, or ± 1%.
[0015] Hereinafter, [basic configuration of yarn] and [characteristics of yarn] will be
described in detail.
[Basic configuration of yarn]
[0016] The yarn of the present disclosure contains, for example, a plurality of "potential-generating
filaments" or "electric field-forming filaments". The number of the potential-generating
filaments or the electric field-forming filaments is not particularly limited, and
for example, 2 or more, 2 to 500, preferably 10 to 350, and more preferably about
20 to 200 potential-generating filaments may be included in the yarn of the present
disclosure.
[0017] In the present disclosure, a "potential-generating filament" or an "electric field-forming
filament" means a fiber (or filament) capable of generating a potential and forming
an electric field by generating charges by external energy (hereinafter, it may be
referred to as "charge-generating fiber" or "charge-generating filament" or "electric
field-forming fiber").
[0018] The term "potential-generating filament" can be used substantially synonymously with
"electric field-forming filament".
[0019] Examples of the "external energy" which the potential-generating filament can receive
include force from outside (hereinafter, sometimes referred to as "external force"),
specifically, force which makes a yarn or filament to have deformation or strain and/or
a force which is applied in the axial direction of a yarn or filament, more specifically,
tension (e.g., tension in the axial direction of a yarn or filament) and/or stress
or strain force (tensile stress or tensile strain applied to a yarn or filament) and/or
external force such as force applied in the transverse direction of a yarn or filament.
[0020] The dimension (length, thickness (diameter), and the like) and the shape (cross-sectional
shape and the like) of the potential-generating filament are not particularly limited.
The yarn of the present disclosure containing such a potential-generating filament
may contain a plurality of potential-generating filaments differing in thickness.
Therefore, the yarn of the present disclosure may or may not have a constant diameter
in the length direction.
[0021] The potential-generating filament may be a long fiber or may be a short fiber. The
potential-generating filament may have a length (or dimension) of, for example, 0.01
mm or more, preferably 0.1 mm or more, more preferably 1 mm or more, even more preferably
10 mm or more, or 20 mm or more, or 30 mm or more. The length may be appropriately
chosen according to a desired application. The upper limit value of the length is
not particularly limited, and is, for example, 10,000 mm, 100 mm, 50 mm, or 15 mm.
[0022] The thickness of the potential-generating filament, that is, the single fiber diameter
is not particularly limited, and may be the same (or constant) or may not be the same
along the length of the potential-generating filament. The potential-generating filament
may have a single fiber diameter of, for example, 0.001 µm (1 nm) to 1 mm, preferably
0.01 µm to 500 µm, more preferably 0.1 µm to 100 µm, and particularly 1 µm to 50 µm,
such as 10 µm or 30 µm. The single fiber diameter may be appropriately chosen according
to a desired application.
[0023] The shape, especially, cross-sectional shape of the potential-generating filament
is not particularly limited, and may have, for example, a circular, elliptical, or
profiled cross section. It is preferable to have a circular cross-sectional shape.
[0024] The potential-generating filament preferably contains a material having a photoelectric
effect, a material having a pyroelectric effect, or a material having a piezoelectric
effect (polarization phenomenon due to external force) or piezoelectricity (the property
of generating a voltage when a mechanical strain is applied or, conversely, generating
a mechanical strain when a voltage is applied) (hereinafter, sometimes referred to
as a "piezoelectric material" or a "piezoelectric substance"). Among them, it is particularly
preferable to use a fiber containing a piezoelectric material (hereinafter, sometimes
referred to as "piezoelectric fiber"). Since the piezoelectric fiber can form an electric
field by piezoelectricity, more specifically, can generate a potential, a power supply
is unnecessary, and there is no risk of electric shock. In addition, the life of the
piezoelectric material that can be contained in the piezoelectric fiber lasts longer
than the antibacterial effect by a chemical agent or the like. Such piezoelectric
fibers are less likely to cause allergic reactions.
[0025] As the "piezoelectric material", any material having a piezoelectric effect or piezoelectricity
can be used without particular limitation, and may be an inorganic material such as
piezoelectric ceramics or may be an organic material such as a polymer.
[0026] The "piezoelectric material" (or "piezoelectric fiber") preferably contains a "piezoelectric
polymer".
[0027] Examples of the "piezoelectric polymer" include a "piezoelectric polymer having pyroelectricity"
and a "piezoelectric polymer having no pyroelectricity".
[0028] "Piezoelectric polymer having pyroelectricity" generally means a piezoelectric material
composed of a polymeric material that has pyroelectricity and is capable of generating
charges on its surface upon application of temperature changes. Examples of such a
piezoelectric polymer include polyvinylidene fluoride (PVDF). In particular, one capable
of generating electric charges on the surface thereof by thermal energy from a human
body is preferable.
[0029] "Piezoelectric polymer having no pyroelectricity" generally means a piezoelectric
polymer (hereinafter, sometimes referred to as "polymeric piezoelectric substance")
composed of a polymer material (polymeric material or resin material) and excluding
the "piezoelectric polymer having pyroelectricity" described above. Examples of such
a piezoelectric polymer include polylactic acid (PLA).
[0030] As the polylactic acid (PLA), poly-L-lactic acid (PLLA), in which an L-form monomer
is polymerized, (in other words, a polymer composed substantially only of repeating
units derived from L-lactic acid monomers), poly-D-lactic acid (PDLA), in which a
D-form monomer is polymerized, (in other words, a polymer composed substantially only
of repeating units derived from D-lactic acid monomers), and mixtures thereof are
known.
[0031] As the polylactic acid (PLA), a copolymer of L-lactic acid and/or D-lactic acid with
a compound copolymerizable with the L-lactic acid and/or D-lactic acid may be used.
[0032] A mixture of "polylactic acid (a polymer substantially composed of repeating units
derived from a monomer selected from the group consisting of L-lactic acid and D-lactic
acid)" and "a copolymer of L-lactic acid and/or D-lactic acid and a compound copolymerizable
with L-lactic acid and/or D-lactic acid" may also be used.
[0033] In the present disclosure, the polymer containing polylactic acid is referred to
as a "polylactic acid-based polymer". In other words, the "polylactic acid-based polymer"
means "polylactic acid (a polymer substantially composed of repeating units derived
from a monomer selected from the group consisting of L-lactic acid and D-lactic acid)",
a "copolymer of L-lactic acid and/or D-lactic acid and a compound copolymerizable
with L-lactic acid and/or D-lactic acid", and mixtures thereof.
[0034] Among polylactic acid-based polymers, "polylactic acid" is particularly preferable,
and it is most preferable to use a homopolymer of L-lactic acid (PLLA) and a homopolymer
of D-lactic acid (PDLA).
[0035] The polylactic acid-based polymer may have a crystalline portion, or at least a part
of the polymer may be crystallized. As the polylactic acid-based polymer, it is preferable
to use a polylactic acid-based polymer having piezoelectricity, in other words, a
piezoelectric polylactic acid-based polymer, especially a piezoelectric polylactic
acid.
[0036] Besides the polylactic acid-based polymer, for example, optically active polymers,
such as polypeptide-based polymers (e.g., poly(γ-benzyl glutarate) and poly(γ-methyl
glutarate)), cellulose-based polymers (e.g., cellulose acetate and cyanoethylcellulose),
polybutyric acid-based polymers (e.g., poly(β-hydroxybutyric acid)), and polypropylene
oxide-based polymers, and derivatives thereof may be used as a polymeric piezoelectric
substance.
[0037] The yarn of the present disclosure may contain a potential-generating filament (or
a charge-generating fiber) having a configuration in which a conductor is used as
a core yarn, an insulator is wound around the conductor, and a voltage is applied
to the conductor to generate charges or a potential.
[0038] The yarn of the present disclosure may be a yarn obtained by simply paralleling a
plurality of potential-generating filaments (a paralleled yarn or a non-twisted yarn),
or may be a yarn provided with twist (a co-twisted yarn or a twisted yarn), or may
be a yarn provided with crimp (a crimped yarn or a false twisted yarn).
[0039] For example, as illustrated in Fig. 1(A), the yarn 1 can be configured by co-twisting
a plurality of potential-generating filaments 10. In an aspect illustrated in Fig.
1(A), the yarn 1 is a left-twisted yarn (hereinafter, referred to as "S yarn") in
which the potential-generating filament 10 is twisted to the left, but may be a right-twisted
yarn (hereinafter, referred to as "Z yarn") in which the potential-generating filament
10 is twisted to the right (see, e.g., yarn 2 of Fig. 3(A)). Thus, in the case of
a co-twisted yarn, the yarn of the present disclosure may be either an "S yarn" or
a "Z yarn".
[0040] In the yarn of the present disclosure, the distance between potential-generating
filaments 10 is about 0 µm to about 10 µm, typically about 5 µm. When the interval
between the potential-generating filaments 10 is 0 µm, it means that the potential-generating
filaments are in contact with each other. When being within the above range, in the
yarn of the present disclosure, the targeted value of specific permittivity of "about
4.5 or less" described in detail below is suitably obtained, and an antibacterial
property can be more reliably exhibited.
[0041] Herein, the specific permittivity of the yarn of the present disclosure means the
ratio of the permittivity of the yarn of the present disclosure to the permittivity
of a vacuum ([the specific permittivity of the yarn of present disclosure] = [the
permittivity of the yarn of present disclosure]/[the permittivity of vacuum]). The
specific permittivity is a dimensionless numerical value, and may be referred to as
a relative permittivity or a dielectric constant.
[0042] The specific permittivity of the yarn of the present disclosure can be determined,
for example, by measuring a capacitance by passing the yarn through a parallel plate
capacitor, calculating a capacitance of the yarn from a difference between the measured
capacitance and a capacitance attained when the yarn is not passed, determining a
permittivity of the yarn of the present disclosure by using the capacitance of the
yarn and the volume of the yarn, and then calculating the specific permittivity based
on the above formula using a permittivity of a vacuum.
[0043] The method for determining the specific permittivity of the yarn is not limited to
the method described above. For example, as described in detail with reference to
the photograph of Fig. 12, especially Fig. 12(B), and the like, the specific permittivity
of the yarn of the present disclosure may be directly measured using a measuring instrument
such as an LCR meter (e.g., Precision LCR Meter (model: E4980A) manufactured by Agilent
Technologies, Inc.). In this case, the specific permittivity of the yarn can be directly
measured using a yarn bundle (sample) formed by collecting the yarns of the present
disclosure (see Figs. 11 to 13).
[0044] The measured value of the specific permittivity in the yarn bundle shows substantially
the same result as the calculated value of the specific permittivity of the yarn (one
yarn) of the present disclosure based on the capacitance described above.
[0045] Hereinafter, in order to describe the yarn of the present disclosure in detail, the
yarn of the present disclosure will be described in more detail with reference to
Figs. 1 to 3 by taking an aspect in which a piezoelectric material is contained as
a potential-generating filament and the piezoelectric material is "polylactic acid"
as an example.
[0047] The optical purity of polylactic acid (PLA) as a piezoelectric material is a value
calculated by the following formula.

[0048] For example, with both of the D-form and the L-form, the optical purity is 90% by
weight or more, preferably 95% by weight or more, more preferably 98% by weight or
more and 100% by weight or less, even more preferably 99.0% by weight or more and
100% by weight or less, and particularly preferably 99.0% by weight or more and 99.8%
by weight or less. As the amount of the L-form and the amount of the D-form of polylactic
acid (PLA), for example, values obtained by a method using high performance liquid
chromatography (HPLC) can be used.
[0049] The crystallinity of polylactic acid (PLA) is, for example, 35% or more (specifically,
35% or more and 45% or less, and more specifically, 42% or more and 44% or less),
more preferably 50% or more, and even more preferably 55% or more and 100% or less.
The crystallinity can be determined by a measurement method such as a method using
a differential scanning calorimetry (DSC) (e.g., DSC 7000X manufactured by Hitachi
High-Tech Science Corporation) and X-ray diffraction (XRD) (e.g., an X-ray diffraction
method using ultraX 18 manufactured by Rigaku Corporation). When the crystallinity
is within the above range, the charge and potential that can be generated in the yarn
can be more appropriately controlled.
[0050] As illustrated in Fig. 1(A), the potential-generating filament (or piezoelectric
fiber) 10 containing uniaxially drawn polylactic acid has tensor components of d
14 and d
25 as piezoelectric strain constants where a thickness direction is defined as a first
axis, a drawing direction 900 is defined as a third axis, and a direction orthogonal
to both the first axis and the third axis is defined as a second axis.
[0051] Therefore, polylactic acid can most efficiently generate charges or a potential when
strain occurs in a direction of 45 degrees with respect to the uniaxially drawn direction.
[0052] The number average molecular weight (Mn) of polylactic acid is, for example, 6.2
× 10
4, and the weight average molecular weight (Mw) is, for example, 1.5 × 10
5. The molecular weight is not limited to these values.
[0053] Figs. 2(A) and 2(B) are diagrams showing the relationship among the uniaxial drawing
direction of polylactic acid, the electric field direction, and the deformation of
the potential-generating filament (or piezoelectric fiber) 10.
[0054] As illustrated in Fig. 2(A), when the filament 10 contracts in the direction of a
first diagonal line 910A and expands in the direction of a second diagonal line 910B
orthogonal to the first diagonal line 910A, an electric field can be generated in
a direction from the back side toward the front side of the diagram. That is, the
filament 10 can generate negative charges or a potential on the front side of the
diagram. As illustrated in Fig. 2(B), the filament 10 can generate charges even when
expanding in the direction of the first diagonal line 910A and contracting in the
direction of the second diagonal line 910B, but the polarity is reversed, and an electric
field can be generated in a direction from the front side of the diagram toward the
back side of the diagram. That is, the filament 10 can generate positive charges or
a potential on the front side of the diagram.
[0055] Polylactic acid can have piezoelectricity due to molecular orientation processing
by drawing, crystallinity, etc., and thus does not need to be subjected to poling
processing unlike other piezoelectric polymers such as polyvinylidene fluoride (PVDF)
or piezoelectric ceramics. The uniaxially drawn polylactic acid has a piezoelectric
constant of about 5 to 30 pC/N, and has a very high piezoelectric constant among polymers.
Furthermore, the piezoelectric constant of polylactic acid does not vary with time
and is extremely stable.
[0056] The potential-generating filament 10 is preferably a fiber having a circular cross
section. The potential-generating filament 10 can be manufactured by, for example,
a method of extruding and molding a piezoelectric polymer to form a fiber, a method
of melt-spinning a piezoelectric polymer to form a fiber (examples thereof including
a spinning-drawing method in which a spinning step and a drawing step are separately
performed, a direct drawing method in which a spinning step and a drawing step are
connected, a POY-DTY method in which false twisting step can also be performed simultaneously,
or an ultrahigh speed spinning method with an increased speed), a method of forming
a fiber from a piezoelectric polymer by a dry or wet spinning method (examples thereof
including a phase separation method or a dry-wet spinning method in which a feed polymer
is dissolved in a solvent and the solution is extruded through a nozzle to form a
fiber, a gel-spinning method of uniformly forming a fiber in a gel state with a solvent
contained, or a liquid crystal spinning method of forming a fiber using a liquid crystal
solution or a liquid crystal melt), or a method of forming a fiber from a piezoelectric
polymer by electrostatic spinning. The cross-sectional shape of the potential-generating
filament 10 is not limited to a circular shape.
[0057] For example, the yarn 1 illustrated in Fig. 1 may be a yarn obtained by twisting
a plurality of such potential-generating filaments 10 containing polylactic acid (multifilament
yarn) (S yarn). The number of filaments 10 constituting the yarn 1 is not particularly
limited. The drawing direction 900 of each potential-generating filament 10 coincides
with the axial direction of each potential-generating filament 10. Therefore, the
drawing direction 900 of the potential-generating filament 10 is inclined to the left
with respect to the axial direction of the yarn 1. The angle may depend on the number
of twists.
[0058] When a tension is applied to the yarn 1, which is such an S yarn, negative charges
or a potential is generated on the surface of the yarn 1, and positive charges or
a potential can be generated on the inner side thereof.
[0059] The yarn 1 can form an electric field by a potential difference that can be generated
by the charge. This electric field leaks also into a space in the vicinity and can
form a combined electric field with other portions. Furthermore, when a potential
that can be generated in the yarn 1 is brought close to a prescribed potential, for
example, an object having a prescribed potential (including a ground potential) such
as a human body, the potential can also generate an electric field between the yarn
1 and the object.
[0060] Next, referring to Fig. 3, since the yarn 2 is a Z yarn, the drawing direction 900
of the potential-generating filament (or piezoelectric fiber) 10 is inclined to the
right with respect to the axial direction of the yarn 2. The angle can depend on the
number of twists of the yarn. The number of filaments 10 constituting the yarn 2 is
also not particularly limited.
[0061] When a tension is applied to the yarn 2, which is such a Z yarn, a positive charge
or potential is generated on the surface of the yarn 2, and a negative charge or potential
can be generated on the inner side thereof.
[0062] The yarn 2 also can form an electric field by a potential difference that can be
generated by the charge. This electric field leaks also into a space in the vicinity
and can form a combined electric field with other portions. Furthermore, when a potential
that can be generated in the yarn 2 is brought close to a prescribed potential, for
example, an object having a prescribed potential (including a ground potential) such
as a human body, the potential can also generate an electric field between the yarn
2 and the object.
[0063] Furthermore, when the yarn 1, which is an S yarn, and the yarn 2, which is a Z yarn,
are brought close to each other, an electric field or potential can be generated between
the yarn 1 and the yarn 2.
[0064] The polarities of charges or potentials that can be generated in the yarn 1 and the
yarn 2 are different from each other. The potential difference at each position can
be defined by an electric field coupled circuit formed by complexly entangling the
fibers with each other or a circuit formed by an electric current path that is formed
by accident in the yarn by the action of moisture or the like.
[0065] The yarn of the present disclosure should not be construed as limited to the above
aspects. The method for manufacturing the yarn of the present disclosure is also not
particularly limited, and is not limited to the manufacturing method described above.
[0066] Furthermore, the yarn of the present disclosure may be provided with a "dielectric"
on at least a part of a periphery of the potential-generating filament, for example
on at least a part of a surface in the longitudinal axial direction and/or the circumferential
direction of the filament.
[0067] For example, as schematically illustrated in the cross-sectional view of Fig. 4,
a dielectric 100 can be provided around the potential-generating filament (or piezoelectric
fiber) 10.
[0068] In the yarn of the present disclosure, the "dielectric" is an arbitrary constituent,
and is not an essential constituent of the invention.
[0069] In the present disclosure, the "dielectric" means a material or a substance containing
a material or a substance having a dielectric property (a property of being electrically
polarized by an electric field) and/or conductivity (a property of passing electricity),
and for example, can accumulate charges on a surface thereof.
[0070] The specific permittivity of the yarn of the present disclosure may be more appropriately
adjusted within a range of "about 4.5 or less", for example, a range of "about 1 to
about 4.5" by providing a "dielectric" on a surface of the yarn or the potential-generating
filament of the present disclosure, for example, on a surface of the potential-generating
filament in a cross-sectional view or a radial cross section. For example, an electric
field having a larger electric field intensity (for example, 0.1 V/µm or more) can
be formed by lowering the specific permittivity to, for example, close to 1. In other
words, at least a part of the yarn or the potential-generating filament of the present
disclosure may be covered with a dielectric such that the specific permittivity of
the yarn is about 1 to about 4.5.
[0071] The dielectric may be present, for example, in the longitudinal axial direction and
the circumferential direction of the potential-generating filament, and may completely
or partially cover the potential-generating filament.
[0072] Therefore, the dielectric may be provided entirely or partially in the longitudinal
axial direction of the potential-generating filament. In addition, the dielectric
may be provided entirely or partially in the circumferential direction of the potential-generating
filament.
[0073] In addition, the dielectric may be uniform or non-uniform in thickness (see, e.g.,
Fig. 4). The thickness of the dielectric may be larger or smaller than the fiber diameter
of the potential-generating filament. The thickness of the dielectric is preferably
smaller than the fiber diameter of the potential-generating filament (see Fig. 4).
[0074] The dielectric may be provided in layer on a surface of the yarn or the potential-generating
filament of the present disclosure, for example, on at least a part of a surface of
the yarn or the potential-generating filament of the present disclosure in a cross-sectional
view or a radial cross-section of the potential-generating filament. The dielectric
may also be present between potential-generating filaments, and in this case, there
may be a part where the dielectric is not present between the potential-generating
filaments. In addition, bubbles or cavities may be present in the dielectric.
[0075] The dielectric is not particularly limited as long as it contains a material or a
substance having dielectric properties, conductivity, and the like. As the dielectric,
a dielectric material (for example, an oil agent, an antistatic agent, and the like)
known to be usable mainly as a surface treating agent (or a fiber treating agent)
in the fiber industry may be used.
[0076] In the yarn of the present disclosure, the dielectric preferably contains an oil
agent. As the oil agent, an oil agent usable as a surface treating agent (or a fiber
treating agent) usable in the manufacture of the potential-generating filament can
be used. In addition, an oil agent usable as a surface treating agent (or a fiber
treating agent) usable in a step of manufacturing fabric (for example, knitting, weaving,
and the like) and an oil agent usable as a surface treating agent (or a fiber treating
agent) usable in a finishing step can also be used. Here, as a representative example,
a filament manufacture step, a fabric manufacture step, and a finishing step have
been mentioned, but the present invention is not limited to these steps. As the oil
agent, it is preferable to use a surface treating agent (or a fiber treating agent)
such as an oil agent usable particularly for reducing friction of the potential-generating
filament.
[0077] Examples of the oil agent include DELION series manufactured by TAKEMOTO OIL & FAT
Co., Ltd., MARPOZOL series and MARPOZIES series manufactured by Matsumoto Yushi-Seiyaku
Co., Ltd., and Paralatex series manufactured by MARUBISHI OIL CHEMICAL CO., LTD.
[0078] The oil agent may be present entirely or at least partially along the potential-generating
filament. After the potential-generating filament is processed into a yarn, part of
the oil agent may fall off from the potential-generating filament by washing.
[0079] In addition, the dielectric usable to reduce friction of the potential-generating
filament may be a surfactant such as a detergent or a softener that can be used during
washing.
[0080] Examples of the detergent include Attack series manufactured by Kao Corporation,
TOP series manufactured by Lion Corporation, and ARIEL series manufactured by Procter
& Gamble Japan K.K.
[0081] Examples of the softener include Humming series manufactured by Kao Corporation,
SOFLAN series manufactured by Lion Corporation, and LENOR series manufactured by Procter
& Gamble Japan K.K.
[0082] The dielectric may have conductivity (property of passing electricity), and in this
case, the dielectric preferably contains an antistatic agent. As the antistatic agent,
an antistatic agent usable as a surface treating agent (or a fiber treating agent)
usable in the manufacture of the potential-generating filament can be used. As the
antistatic agent, it is preferable to use an antistatic agent that can be used particularly
for reducing the loosening of the potential-generating filament.
[0083] By containing at least one selected from the group consisting of surface treating
agents (or fiber treating agents) such as oil agents and antistatic agents, detergents,
softeners, and the like as a dielectric, a specific permittivity adjusted within a
range of about 1.0 or more and about 4.5 or less can be imparted to the yarn.
[0084] Examples of the antistatic agent include Capron series manufactured by NISSIN KAGAKU
KENKYUSHO CO.,LTD., NICEPOLE series and DEATRON series manufactured by NICCA CHEMICAL
CO., LTD. Among them, NICEPOLE series manufactured by NICCA CHEMICAL CO., LTD. is
preferable, and those containing an ester-based polymer such as a polyester-based
polymer, especially a PEG-modified polyester-based polymer are preferable (for example,
NICEPOLE PR-99). By using such an antistatic agent, a specific permittivity adjusted
within a range of about 1.0 or more and about 4.5 or less can be imparted to the yarn.
[0085] As the antistatic agent, a surface treating agent (or a fiber treating agent) capable
of imparting water absorbency and/or SR property (soil removability) together with
an antistatic effect may be used. Examples of such an antistatic agent include Water
absorbent/SR agent series manufactured by Takamatsu Oil & Fat Co., Ltd. (e.g., SR-1800
containing a polyester-based polymer); and QUEENSTAT series manufactured by Kotani
Chemical Industry Co., Ltd. (e.g., QUEENSTAT NW-E conc, which contains a urethane-based
polymer, especially, a crosslinkable hydrophilic urethane-based polymer and can impart
a water absorbent SR property and an antistatic effect). By using such an antistatic
agent, a specific permittivity adjusted within a range of about 1.0 or more and about
4.5 or less can be imparted to the yarn.
[0086] The antistatic agent may be present entirely or at least partially along the potential-generating
filament, for example, on the longitudinal axial and/or the circumferential surface
of the potential-generating filament. After the potential-generating filament is processed
into a yarn, part of the antistatic agent may fall off from the potential-generating
filament by washing.
[0087] In the yarn of the present disclosure, the dielectric may be a "metal oxide". As
the metal oxide, it is preferable to use a metal oxide having conductivity (property
of passing electricity). For example, at least one of a metal oxide selected from
the group consisting of titanium oxide, tungsten oxide, zinc oxide, zirconium oxide,
niobium oxide, antimony oxide, tin oxide, indium oxide, cerium oxide, aluminum oxide,
silicon oxide, magnesium oxide, yttrium oxide, ytterbium oxide, and tantalum oxide,
or a composite oxide thereof can be used.
[0088] The metal oxide may be present entirely or at least partially along the potential-generating
filament, for example, on the longitudinal axial and/or the circumferential surface
of the potential-generating filament.
[0089] By using such a metal oxide, a specific permittivity adjusted within a range of about
4.5 or less, preferably about 3.0 or more and about 4.0 or less can be imparted to
the yarn.
[0090] The dielectric preferably contains titanium oxide (TiO
2) as a metal oxide because such a dielectric can exhibit not only conductivity but
also antibacterial properties by photocatalysis.
[0091] The amount of a surface treating agent (or a fiber treating agent) such as an oil
agent or an antistatic agent, a detergent, a softener, a metal oxide, or the like
adhering to the potential-generating filament is not particularly limited as long
as the above-described specific permittivity can be achieved.
[0092] In the case of a surface treating agent (or a fiber treating agent) such as an oil
agent or an antistatic agent, a detergent, or a softener, the amount of adhesion to
the potential-generating filament is, for example, 1% by weight or more and 20% by
weight or less, preferably 1% by weight or more and 15% by weight or less, and more
preferably 4% by weight or more and 15% by weight or less based on 100% by weight
of the potential-generating filament.
[0093] In the case of a metal oxide, the amount of adhesion to the potential-generating
filament is, for example, 0.1% by weight or more and 5% by weight or less, preferably
0.1% by weight or more and 1% by weight or less, and more preferably 0.1% by weight
or more and 0.5% by weight or less based on 100% by weight of the potential-generating
filament.
[0094] In addition, a surface treating agent (or a fiber treating agent) such as the above-described
oil agent or antistatic agent, a detergent, a softener, a metal oxide, or the like
may not be present around the potential-generating filament. That is, the potential-generating
filament, and thus the yarn of the present disclosure may not contain a surface treating
agent or the like. In such a case, air that may be present between or in gaps between
the potential-generating filaments and/or around the filaments may function as a dielectric.
Thus, in this case, the dielectric contains air or an air layer.
[0095] When a surface treating agent (or a fiber treating agent) such as the oil agent or
the antistatic agent described above, a detergent, a softener, a metal oxide, or the
like is not present around the potential-generating filament, in other words, when
the potential-generating filament is untreated or unprocessed, the potential-generating
filament may have a specific permittivity adjusted within a range of, for example,
about 1.0 or more and about 3.0 or less, preferably about 1.0 or more and about 2.6
or less, and more preferably about 1.0 or more and about 2.0 or less.
[0096] In the present disclosure, when a surface treating agent (or a fiber treating agent)
such as the oil agent or the antistatic agent described above, a detergent, a softener,
a metal oxide, or the like is not present around the potential-generating filament,
in other words, when only an air layer is present around the filament, the presence
of an extremely small amount of component that can be unavoidably or accidentally
mixed during the manufacture of the yarn or the filament can be permitted.
[0097] The thickness of the dielectric (or the interval between the potential-generating
filaments) is about 0 µm to about 10 µm, preferably about 0.5 µm to about 10 µm, more
preferably about 2.0 µm to about 10 µm, and typically about 5 µm. When being within
such a range, in the yarn of the present disclosure, the targeted value of specific
permittivity of "about 4.5 or less" described in detail below is suitably obtained,
and an antibacterial property can be more reliably exhibited.
[0098] In the yarn of the present disclosure, the "dielectric" can have a specific permittivity
(ε) of about 1.0 to about 5.0, preferably a specific permittivity (ε) of about 2.0
to about 5.0, more preferably about 3.0 to about 5.0, even more preferably about 3.5
to about 5.0, and particularly preferably about 4.0 to about 5.0 (Fig. 5). When being
within such a range, in the yarn of the present disclosure, the targeted value of
specific permittivity of "about 4.5 or less" described in detail below is suitably
obtained, and an antibacterial property can be more reliably exhibited.
[0099] Regarding the specific permittivity of a yarn, for example, the yarn is sandwiched
between a pair of electrodes of an LCR meter or the like, a potential is applied between
the two electrodes, an electrostatic capacitance is calculated from the amount of
charge generated in the electrodes and the applied potential, and the specific permittivity
of the yarn can be calculated from the electrostatic capacitance, the area of the
electrodes, and the distance between the electrodes.
[Characteristics of yarn]
[0100] The yarn of the present disclosure has, as a physical property thereof, a specific
permittivity of about 4.5 or less, for example, about 1.0 or more and about 4.5 or
less.
[0101] The lower limit value of the specific permittivity may be about 1.5, about 2.0, about
2.5, about 2.6, about 3.0, about 3.5, or about 4.0.
[0102] The upper limit value of the specific permittivity may be about 4.0, about 3.5, about
3.0, about 2.6, about 2.5, about 2.0, or about 1.5.
[0103] As the upper limit and the lower limit of the specific permittivity, the above values
may be combined, as necessary.
[0104] With such physical property values, antibacterial properties can be obtained more
reliably in the present invention. It has become apparent for the first time from
the research by the present inventors that the antibacterial property can be more
reliably obtained based on physical property values of the yarn such as the specific
permittivity. The mechanism and the background of the research that led to the discovery
of such physical properties and antibacterial property will be described in detail
below.
(Mechanism)
[0105] As a result of intensive research by the present inventors, for example, when a yarn
is viewed in a cross-sectional view or a radial cross section, it has been previously
found that the strength of the electric field that can be formed in the yarn decreases
depending on the state of the space and/or gap between the potential-generating filaments,
particularly the permittivity of the dielectric (including the air layer) that can
be present between the potential-generating filaments and/or the physical properties
such as dielectric constant of the yarn itself, and for example, a desired or a certain
(level) antibacterial property may not be obtained.
[0106] In addition, as demonstrated in the preliminary test of the following Examples (Fig.
8), etc., the research by the present inventors has revealed that the value of "voltage
(or potential)" is more dominantly involved in the antibacterial action than the value
of electric current.
[0107] Here, briefly explaining a germ to be taken as a target, bacteria and fungi, particularly
fungi, are composed of elongated hyphae and spores having a basically circular shape.
In addition, it is known that spores proliferate by germination, and when they float
in the air or the like and adhere to parasites, they form hyphae and reproduce both
sexually and asexually ("
Textbook of Modern Dermatology", 2nd edition, written by Hiroshi SHIMIZU, page 469). The size of spores that contribute to such proliferation is generally about 2 µm
to about 10 µm ("
Window of Food Sanitation", the website of Bureau of Social Welfare and Public Health,
Tokyo Metropolitan Government).
[0108] Next, briefly explaining the antibacterial action by electrical stimulation, it has
been conventionally known that proliferation of germs can be suppressed by an electric
field (see, for example,
Tetsuaki Tsuchido, Hiroki Kourai, Hideaki Matsuoka, and Junichi Koizumi "Microbial
Control-Science and Engineering": Kodansha; and see for example,
Koichi Takaki "Agricultural and Food Processing Applications of High-Voltage and Plasma
Technologies", J. HTSJ, Vol. 51, No. 216).
[0109] In addition, it has also been known that: by virtue of a potential that generates
such an electric field, a current may flow through a current path formed by moisture
or the like or a circuit that can be formed by a local micro discharge phenomenon
or the like, and germs are weakened by such an electric current and the proliferation
of germs can be suppressed.
[0111] According to the above document, the condition under which electroporation that destroys
cell membranes of germs and the like occurs is generally that a potential difference
(or voltage) of "about 1.0 V" is applied to cells, and the present inventors have
considered that, for example, in a case where the size of a spore is about 2 µm to
about 10 µm, when an electric field or potential having an electric field intensity
of about 0.1 V/µm or more is generated, a potential difference (or voltage) of about
1.0 V or more can be applied even in the case of a spore having a size of about 10
µm at the maximum, so that cell membranes may be destroyed due to the occurrence of
electroporation, or an electron transfer system for life support may be hindered,
leading to weakening, killing, or reduction of cells.
[0112] Based on such considerations, the present inventors first studied the relationship
of the electric field intensity (V/µm) of an electric field with the permittivity,
e.g., the permittivity of a dielectric, which is considered to affect the antibacterial
property; especially, the relationship with the "specific permittivity (ε)" of the
dielectric.
[0113] As a result, it has been revealed that: as shown for example in the graph of Fig.
5, if for example the value of the specific permittivity (ε) of a dielectric that
can be provided on a piezoelectric fiber is within a range of about 1.0 to about 5.0,
preferably about 3.5 to about 5.0, and more preferably about 4.0 to about 5.0, when
an external force, e.g., a tension of about 0.15%, e.g., a tensile strain (in other
words, a tension in the axial direction of the fiber and a tensile stress applied
to the fiber) is applied, an electric field having an electric field intensity of
about 0.1 V/µm or more can be formed.
[0114] Here, regarding Fig. 5, the value (V/µm) of the electric field intensity for the
specific permittivity (ε) of the dielectric at each filament interval (X: 0.5 µm,
Y: 2 µm, Z: 5 µm) is more specifically as shown in the following table. The graph
shown in Fig. 5 merely exemplifies the relationship between the specific permittivity
of the dielectric and the electric field intensity.
[Table 1]
|
Filament interval |
X 0.5 µm |
Y 2 µm |
Z 5 µm |
Specific permittivity (ε) |
1 |
0.133802 |
0.14448 |
0.150119 |
3 |
0.105362 |
0.113549 |
0.111665 |
5 |
0.091435 |
0.096983 |
0.09158 |
7 |
0.081765 |
0.085222 |
0.078101 |
9 |
0.074336 |
0.076186 |
0.068243 |
[0115] As a result of further research, it has been found that the specific permittivity
of the yarn similarly affects the antibacterial property. Then, it has been found
that when the specific permittivity of the yarn is about 4.5 or less, preferably in
a range of about 1.0 to about 4.5, an electric field or potential having an electric
field intensity of about 0.1 V/µm or more can be formed when external energy such
as external force, for example, external energy such as tensile force or tensile strain
of at least 0.15% is applied.
[0116] Here, the electric field intensity can be measured by using, for example, a scanning
probe microscope, a surface electrometer, or the like.
[0117] Specifically, first, using a scanning probe microscope, displacement of a minute
probe due to electric attractive force or repulsive force caused by bringing the probe
to which a weak voltage is applied close to an object is detected. Next, using a surface
electrometer, a voltage for canceling the electric attractive force or the repulsive
force applied to the minute probe is measured, whereby the value of the surface potential
of the object or the value of the electric field intensity can be obtained.
[0118] The measurement with a scanning probe microscope and a surface electrometer may be
performed using an electric force microscope (for example, Model 1100TN manufactured
by TREK, INC.) having functions of both the instruments.
[0119] Thus, when the "specific permittivity" is a value of "about 4.5 or less" as a physical
property of the yarn, an electric field having an electric field intensity of "about
0.1 V/µm or more" can be formed. As a result, when such an electric field is formed
in a germ such as a fungus having a spore size of about 2 µm to about 10 µm, a potential
difference of 1.0 V or more can be applied even when the spore size is 10 µm at the
maximum, and for example, it is possible to destroy cell membranes by electroporation
to weaken, kill, or reduce germs. In other words, the antibacterial property can be
more reliably exhibited.
[0120] When the value of the "specific permittivity" of the yarn is a value of about 1.0
or more (desirably 4.5 or less), an electric field or potential having an electric
field intensity of about 0.1 V/µm or more can be formed in the same manner as described
above, which is favorable.
[0121] The filament interval (or the thickness of the dielectric) of the yarn of the present
disclosure is typically about 5 µm, and at this time, the "specific permittivity"
of the yarn is about 1.0 to about 2.6, and about 2.0 to about 2.6. Also in this case,
an electric field having an electric field intensity of 0.1 V/µm or more can be formed,
which is favorable.
[0122] Thus, the yarn of the present disclosure can form an electric field or potential
having an electric field intensity of "about 0.1 V/µm or more" due to having a "specific
permittivity" of "about 4.5 or less" as a unique physical property and a value thereof
(a physical property value) found for the first time by the present inventors. By
the direct action of such an electric field or potential, defects are caused in cell
membranes of germs or in an electron transfer system for the life support of germs,
and generation and proliferation of germs can be suppressed. Thus, it is possible
to weaken germs or reduce or kill germs.
[0123] Therefore, in the present disclosure, the "antibacterial property" means that at
least the generation and proliferation of germs is suppressed or prevented by an electric
field or potential having an electric field intensity of about 0.1 V/µm or more that
can be formed by the yarn of the present disclosure. Furthermore, the term "antibacterial
property" as used in the present disclosure may also include weakening of germs and
reduction and killing of germs.
[0124] The antibacterial effect may be indirectly exerted by a potential, electric field,
or electric current that can be generated by the yarn of the present disclosure, and
by an active oxygen species to which the oxygen that may be contained in moisture
is changed, and a radical species generated by the interaction or the catalytic action
of an additive that can be contained in a fiber, or other antibacterial chemical species
(amine derivatives, and the like). In addition, oxygen radicals may be generated in
cells of germs by a stress environment due to the presence of a potential or an electric
field or an electric current that can be generated by the yarn of the present disclosure,
and such oxygen radicals may indirectly exert antibacterial properties. Conceivable
radicals include superoxide anion radicals (active oxygen) and hydroxy radicals.
[0125] Such weakening, killing, or reduction of germs due to the action of such active oxygen
species, radical species, antibacterial chemical species, oxygen radicals, and the
like can also be included in the definition of "antibacterial property" as an antibacterial
effect.
[0126] In the present disclosure, "germ" means all germs such as bacteria and fungi and
is not particularly limited as long as the "antibacterial property" is obtained therewith,
and is a concept including microorganisms such as mites and fleas and/or viruses.
A target germ is preferably a "fungus". A fungus is a type of eukaryotic microorganism
having a cell wall, and is a living organism that parasitizes some organic bodies
because it does not perform photosynthesis or exists in nature in the form of spore.
Among fungi, it is preferable to target dermatophytes, and it is particularly preferable
to target Trichophyton.
[0127] The yarn of the present disclosure has "antibacterial properties" against "germs",
and thus may be referred to as an "antibacterial yarn".
(Other features)
[0128] The yarn (or antibacterial yarn) of the present disclosure may further have the following
physical properties (impedance, resistivity, etc.) and values thereof (physical property
values). The following physical properties and physical property values are also suitable
because antibacterial properties can be obtained more reliably. The following physical
properties and physical property values were found for the first time by the present
inventors through earnest research.
(Impedance)
[0129] In the yarn of the present disclosure, the impedance is about 4.0 × 10
6 Ωm or more, preferably about 4.0 × 10
6 Ωm to about 1.8 × 10
7 Ωm, and typically about 7.0 × 10
6 Ωm.
[0130] When the impedance of the yarn of the present disclosure is within the above range,
an electric field or potential having an electric field intensity of about 0.1 V/µm
or more can be formed, and the antibacterial property can be more reliably achieved.
[0131] In the present disclosure, the "impedance" means an impedance Z per unit volume.
For example, as schematically illustrated in Fig. 6, the impedance Z can be measured
by sandwiching a yarn between two measurement electrodes and connecting the two measurement
electrodes to an LCR meter (or impedance measuring instrument).
[0132] The method of measuring the impedance Z is not limited to the method illustrated
in Fig. 6.
[0133] When the yarn of the present disclosure is regarded as an ideal dielectric, and its
capacitance is C and frequency is 1 kHz, the impedance Z per unit volume of the yarn
of the present disclosure can be expressed by the following formula:

wherein C represents a capacitance.
[0134] Since the capacitance C is proportional to the "specific permittivity" of the yarn
of the present disclosure, the impedance Z is inversely proportional to the "specific
permittivity" of the yarn of the present disclosure.
[0135] Therefore, the lower limit value of the impedance Z, that is "4.0 × 10
6 Ωm", can correspond to the upper limit value of the specific permittivity of the
yarn of the present disclosure, that is "4.5". The upper limit value of the impedance
Z, that is "1.8 × 10
7 Ωm", can correspond to the lower limit value of the specific permittivity of the
yarn of the present disclosure, that is "1.0".
[0136] Thus, the value of the impedance of the yarn can be converted from the specific permittivity
of the yarn.
[0137] A typical impedance value of the yarn of the present disclosure, that is "7.0 × 10
6 Ωm", can correspond to a typical value of the "specific permittivity" of the yarn
of the present disclosure, that is "2.6".
(Resistivity)
[0138] In the yarn of the present disclosure, the resistivity is about 1.4 × 10
4 Ωm or more, and preferably about 1.4 × 10
4 Ωm to about 2.3 × 10
15 Ωm.
[0139] When the resistivity of the yarn of the present disclosure is within the above range,
an electric field or potential having an electric field intensity of about 0.1 V/µm
or more can be formed, and the antibacterial property can be more reliably achieved.
[0140] Reference is now made to Fig. 7. Fig. 7 shows the relationship between the "interval
d (µm) between the potential-generating filaments" (hereinafter, sometimes referred
to as a "filament interval d") and the "electric field intensity (V/µm)" in the yarn
of the present disclosure. The "filament interval d" indicates the shortest distance
(µm) between the surfaces of two potential-generating filaments adjacent to each other.
The filament interval d may also correspond to the thickness of the "dielectric" that
may be present between the filaments.
[0141] Typically, the resistivity of the "dielectric" is less than the resistivity of the
"potential-generating filament" (for example, the resistivity of the antistatic agent:
about 1 × 10
3 Ωm). The resistivity of the yarn of the present disclosure tends to decrease as the
"filament interval d" increases.
[0142] Regarding the yarn of the present disclosure as an ideal resister, for example, when
the "filament interval d" is "5 µm" (the filament interval of the yarn of the present
disclosure (or the thickness of the dielectric) is typically about 5 µm), the "electric
field intensity" is "about 0.1 V/µm" as illustrated in Fig. 7, and the "resistivity"
of the yarn of the present disclosure in this case is "about 1.4 × 10
4 Ωm", which can correspond to the lower limit value (about 1.4 × 10
4 Ωm). When the "filament interval d" is "0 µm", the "resistivity" of the yarn of the
present disclosure is maximum, and the value thereof is "about 2.3 × 10
15 Ωm", which can correspond to the above upper limit value (about 2.3 × 10
15 Ωm).
[0143] Thus, the value of the resistivity of the yarn can also be calculated from the electric
field intensity of the yarn.
[0144] Here, as to Fig. 7, the electric field intensity (V/µm) versus the filament interval
d (µm) is more specifically as shown in the following table.
[Table 2]
d [µm] |
Electric field intensity [V/µm] |
1 |
0.1016814 |
2 |
0.1044287 |
3 |
0.1041357 |
4 |
0.1025711 |
5 |
0.1004682 |
6 |
0.09817822 |
7 |
0.09577033 |
8 |
0.09339429 |
9 |
0.091025 |
10 |
0.08868541 |
[0145] In the yarn of the present disclosure, the resistivity can be measured with, for
example, an insulation resistance meter.
[0146] In the yarn (or antibacterial yarn) of the present disclosure, the physical properties
and the values (physical property values) thereof at which the antibacterial property
can be more reliably obtained are not limited to the "specific permittivity", "impedance",
and "resistivity" described above.
[Use of yarn]
[0147] The yarn of the present disclosure contains, as potential-generating filaments (or
potential-generating fibers or charge-generating fibers or electric field-forming
fibers), fibers capable of generating potential and forming an electric field by generating
charges by external energy (for example, the application of external energy such as
tensile force or tensile strain of at least 0.15%). Therefore, an electric field or
potential is formed in the vicinity of the yarn or the yarn can generate an electric
field between yarns or even when the yarn is brought close to an object having a prescribed
potential (including a ground potential) such as a human body. As described above,
the antibacterial property can be directly exhibited by such a potential or electric
field.
[0148] Furthermore, the yarn of the present disclosure can also allow an electric current
to flow when the yarn approaches another adjacent fiber or an object having a prescribed
potential such as a human body via moisture such as sweat. The antibacterial property
may be exhibited also by this electric current.
[0149] Therefore, when the yarn of the present disclosure is applied to an article that
can be used in proximity to an object having a prescribed potential such as a human
body, for example, the yarn can exhibit the antibacterial property as described above
by the action of the generated potential, electric field or electric current, particularly
the direct action of the potential or electric field.
[0150] The article or product to which the yarn of the present disclosure can be applied
is not particularly limited, and examples thereof include clothing (general), footwear
(general), and medical supplies (general) such as masks. More specifically, the following
applications are conceivable.
[0151] For example, clothing items in general, particularly, underwear (especially, socks),
towels, footwear in general, for example, insoles for shoes and boots, sportswear
in general, hats, bedding (including duvets, mattresses, sheets, pillows, pillows
covers, and the like), toothbrushes, flosses, various filters (filter and the like
of water purifier, air conditioner, or air purifier), stuffed animals, pet-related
products (mat for pet, clothing for pet, and inner of clothing for pet), various mat
products (foot, hand, toilet seat, or the like), curtains, kitchen utensils (sponges,
cloths, or the like), seats (seats of cars, trains, airplanes or the like), cushioning
materials for motorbike helmets and exterior materials thereof, sofas, medical items
in general, including bandages, gauzes, masks, sutures, clothes for doctors and patients,
and supporters, sanitary items, sporting goods (inner of wear and glove, gauntlet
used in martial arts, or the like), packaging materials, and the like can be cited.
[0152] Of the clothing items, in particular, socks (or supporters) always expand and contract
along joints due to movement such as walking, and thus the yarn of the present disclosure
can generate charges or a potential with high frequency. In addition, socks absorb
moisture such as sweat and serve as a hotbed for the proliferation of germs and the
like, but since the yarn of the present disclosure can suppress the proliferation
of germs, it can produce a remarkable effect for antibacterial purposes for odor prevention.
[0153] The yarn of the present disclosure is considered to be suitable for all applications
requiring antibacterial properties, and the applications are not particularly limited
to the above applications.
(Fabric)
[0154] The yarn of the present disclosure can be processed into a fabric, for example, for
the above applications. Therefore, such a fabric contains the yarn of the present
disclosure, and can be used for the above-mentioned applications and the like as the
above-mentioned "antibacterial fabric" having the above-described antibacterial property.
Examples of the fabric of the present disclosure include woven fabrics, knitted fabrics,
and nonwoven fabrics. These can be manufactured by appropriately processing the yarn
of the present disclosure by a method well known in the art, or the like.
[0155] Hereinafter, the yarn and the fabric of the present disclosure will be described
in more detail by way of examples.
Examples
<Preliminary test for confirming antibacterial action by electrical stimulation>
[0156] A preliminary test for confirming the antibacterial action by electrical stimulation
was performed based on the following procedures (1) to (4).
- (1) Using Trichophyton (fungus) as a germ, a suspension of Trichophyton was prepared
by suspending Trichophyton in a state of germ tube in pure water.
- (2) A voltage was applied to the suspension of Trichophyton under the following conditions.
- (3) The state of Trichophyton after the voltage application is shown in the photograph
of Fig. 8.
- (4) As representative examples of the state change of Trichophyton before and after
the voltage application, photographs of the state change of Trichophyton are shown
in Figs. 9(a) and 9(b) for 20 V x 5 Hz and 50 V × 5 Hz, respectively.
[0157]
- Distance between electrodes
50µm
- Voltage
Condition A: 10V
Condition B: 20V
Condition C: 30V
Condition D: 40V
Condition E: 50V
- Frequency
1Hz
5Hz
10Hz
- Number of measurements
n = 3
(Results)
[0158] The voltage value was increased by changing the voltage every 10 V from 10 V to 50
V (conditions A to E). As a result, it became clear that Trichophyton deforms with
an increase in voltage, and plasma streaming stops in some cases. Figs. 9 (a) and
9 (b) are representative photographs of the deformation of Trichophyton before and
after voltage application, and the deformation of spores and that of hyphae were confirmed,
respectively. In particular, it was confirmed that the plasma streaming of Trichophyton
stopped under voltage conditions D and E.
[0159] On the other hand, it was found that even when the electric current value was increased
by changing the frequency to 1 Hz, 5 Hz, and 10 Hz, the plasma streaming of Trichophyton
might not stop in some cases.
[0160] From the facts described above, it was found that the value of voltage is dominantly
involved in the antibacterial action rather than the value of electric current.
[0161] In addition, the size of spores of Trichophyton used in the preliminary test was
about 5 µm as shown in the photograph of Fig. 10, and it has been found that when
a voltage with an electric field intensity of about 0.2 V/µm or more is applied, a
voltage of about 1.0 V or more is applied from one end of a spore to the other and
Trichophyton is killed or reduced.
[0163] The above preliminary test is merely an example, and is not intended to limit the
present invention.
(Example 1)
Preparation of yarn A
[0164] Yarn A composed of potential-generating filaments (the number of filaments: 24) containing
poly-L-lactic acid (PLLA) as a piezoelectric material was prepared (non-twisted yarn)
(optical purity (L-form) measured and calculated by high performance liquid chromatography
(HPLC): 99% or more, crystallinity measured by ultraX 18 manufactured by Rigaku Corporation:
42 to 44%). The potential-generating filaments contained in the yarn A each contained
therearound an oil agent as a dielectric. It was found that part of the oil agent
was removed from the potential-generating filaments by washing after the manufacture
of the yarn.
Measurement of specific permittivity of yarn A
[0165] The specific permittivity of the yarn A was determined by measuring a capacitance
by passing the yarn A through a parallel plate capacitor, calculating a capacitance
of the yarn A from a difference between the measured capacitance and a capacitance
attained when the yarn A was not passed, determining a permittivity of the yarn A
by use of the measured capacitance and the volume of the yarn, and further determining
the specific permittivity of the yarn A by calculation based on a formula: [specific
permittivity of the yarn A] = [permittivity of the yarn A]/[permittivity of vacuum]
using the permittivity of a vacuum. As a result, the specific permittivity of the
yarn A was found to be about 1.4 (measurement temperature: room temperature (25°C)).
Measurement of electric field intensity of electric field formed by yarn A
[0166] Since the yarn A contains PLLA (optical purity (L-form): 99% or more, crystallinity:
42 to 44%), it has been found that an electric field or potential is generated by
applying external energy such as a tensile strain of at least 0.15%. Furthermore,
since the specific permittivity of the yarn A is 1.4, the electric field formed by
the yarn A was measured using an electric force microscope (for example, Model 1100TN
manufactured by TREK, INC.) including a scanning probe, a surface electrometer, and
the like, and has been found to have an electric field intensity exceeding about 0.1
V/µm.
[0167] In the measurement of the electric field intensity, first, using a scanning probe,
displacement of a minute probe due to electric attractive force or repulsive force
caused by bringing the probe to which a weak voltage was applied close to the yarn
A was detected. Next, using a surface electrometer, a voltage for canceling the electric
attractive force or the repulsive force applied to the minute probe was measured,
whereby the value of the electric field intensity of the yarn A was measured.
Antibacterial property
[0168] From the facts described above, since the yarn A has an electric field intensity
exceeding about 0.1 V/µm, it has been found that the yarn A exhibits a sufficient
antibacterial property against Trichophyton of about 10 µm, for example.
(Example 2)
Preparation of yarn B
[0169] Yarn B composed of potential-generating filaments (the number of filaments: 24) containing
poly-L-lactic acid (PLLA) as a piezoelectric material was prepared (non-twisted yarn)
(optical purity (L-form) measured and calculated by high performance liquid chromatography
(HPLC): 99% or more, crystallinity measured by ultraX 18 manufactured by Rigaku Corporation:
42 to 44%). The potential-generating filaments contained in the yarn B each contained
therearound an antistatic agent as a dielectric. It was found that part of the antistatic
agent was removed from the potential-generating filaments by washing after the manufacture
of the yarn.
Measurement of specific permittivity of yarn B
[0170] The specific permittivity of the yarn B was measured in the same manner as the yarn
A, and it was found to be about 1.4 (measurement temperature: room temperature (25°C)).
Measurement of electric field intensity of electric field formed by yarn B
[0171] Since the yarn B contains PLLA (optical purity (L-form): 99% or more, crystallinity:
42 to 44%), it has been found that an electric field or potential is generated by
applying external energy such as a tensile strain of at least 0.15%. Furthermore,
since the specific permittivity of the yarn B was about 1.4, the electric field formed
by the yarn B was measured in the same manner as the yarn A, and was found to have
an electric field intensity exceeding about 0.1 V/µm.
Antibacterial property
[0172] From the facts described above, since the yarn B has an electric field intensity
exceeding about 0.1 V/µm, it has been found that the yarn B exhibits a sufficient
antibacterial property against Trichophyton of about 10 µm, for example.
(Example 3)
Preparation of yarn C
[0173] Yarn C composed of potential-generating filaments (the number of filaments: 24) containing
poly-L-lactic acid (PLLA) as a piezoelectric material was prepared (non-twisted yarn)
(optical purity (L-form) measured and calculated by high performance liquid chromatography
(HPLC): 99% or more, crystallinity measured by ultraX 18 manufactured by Rigaku Corporation:
42 to 44%). The potential-generating filaments contained in the yarn C did not contain
any surface treating agent, and only an air layer as a dielectric was present therearound.
Measurement of specific permittivity of yarn C
[0174] The specific permittivity of the yarn C was measured in the same manner as the yarn
A, and it was found to be about 1.1 (measurement temperature: room temperature (25°C)).
Measurement of electric field intensity of electric field formed by yarn C
[0175] Since the yarn C contains PLLA (optical purity (L-form): 99% or more, crystallinity:
42 to 44%), it has been found that an electric field or potential is generated by
applying external energy such as a tensile strain of at least 0.15%. Furthermore,
since the specific permittivity of the yarn C was about 1.1, the electric field formed
by the yarn C was measured in the same manner as the yarn A, and was found to have
an electric field intensity exceeding about 0.1 V/µm.
Antibacterial property
[0176] From the facts described above, since the yarn C has an electric field intensity
exceeding about 0.1 V/µm, it has been found that the yarn B exhibits a sufficient
antibacterial property against Trichophyton of about 10 µm, for example.
(Example 4)
Preparation of yarn D
[0177] Yarn D composed of potential-generating filaments (the number of filaments: 24) made
of poly-L-lactic acid (PLLA) as a piezoelectric material was prepared (degreased non-twisted
yarn) (optical purity (L-form) measured and calculated by high performance liquid
chromatography (HPLC): 99% or more, crystallinity measured by ultraX 18 manufactured
by Rigaku Corporation: 42 to 44%).
Measurement of specific permittivity of yarn bundle of yarn D
[0178] The yarn D was set on a bobbin, and the yarn D was laterally aligned through a yarn
path guide such that the yarn D did not overlap in the thickness direction on a winding
cylinder having a diameter of 45 mm using a yarn winding machine manufactured by Murata
Manufacturing Co., Ltd., and the yarn D was wound on the cylinder (rotation speed:
60 rpm, 1 minute) (see Fig. 11(A)).
[0179] The yarn D was cut along the axial direction of the winding cylinder to separate
the yarn D from the winding cylinder, thereby affording a yarn bundle sample (yarn
D) having a width of about 1 cm (see Fig. 11(B)). Both the upper and lower ends in
the longitudinal direction of the yarn bundle sample were fixed at the time of cutting.
[0180] The yarn sample (yarn D) was set in a jig (vise) and fixed with Kapton (registered
trademark) tape (see Fig. 12(A) (the photograph shows merely one example of a measurement
method, and the yarn contained in the yarn bundle sample is different from the yarn
D)).
[0181] The yarn bundle sample (yarn D) was disposed to overlap (thickness: about 50 µm)
between two circular measurement electrodes of an LCR meter (Precision LCR Meter (model:
E4980A) manufactured by Agilent Technologies, Inc.) connected to a fixture (Dielectric
Test Fixture (model: 16451B) manufactured by Agilent Technologies, Inc.), and the
yarn bundle sample was sandwiched and fixed by the two measurement electrodes (see
Fig. 12(B) (the photograph shows merely one example of a measurement method, and the
yarn contained in the yarn bundle sample is different from the yarn D)).
[0182] Here, the relationship between the measurement electrodes of the LCR meter and the
yarn bundle sample is illustrated in Fig. 13. In the case of the yarn bundle sample
illustrated in this schematic diagram, since the yarns D are sandwiched between the
measurement electrodes and adjacent to each other, it was assumed that there was no
gap between a yarn D and another yarn D.
[0183] The sum of the areas S1 and S2 illustrated in Fig. 13 was multiplied by 4, and calculation
was performed with the product taken as the area of the yarn bundle sample (hereinafter,
referred to as "sample area").
[0184] As a result of measuring the specific permittivity of the yarn D over such a sample
area with the LCR meter, the value was about 2.1 (temperature: room temperature (25°C),
frequency: 1 kHz). Details of the measurement are shown in the following Table 3.
(Example 5)
Preparation of yarn E
[0185] Yarn E composed of potential-generating filaments (the number of filaments: 24) made
of poly-L-lactic acid (PLLA) as a piezoelectric material was prepared (degreased non-twisted
yarn) (optical purity (L-form) measured and calculated by high performance liquid
chromatography (HPLC): 99% or more, crystallinity measured by ultraX 18 manufactured
by Rigaku Corporation: 42 to 44%).
Measurement of specific permittivity of yarn bundle of yarn E
[0186] As a result of measuring the specific permittivity of the yarn E with an LCR meter
in the same manner as in the yarn D of Example 4, the value of the specific permittivity
was about 1.9. Details of the measurement are shown in the following Table 3.
(Example 6)
Preparation of yarn F
[0187] A yarn composed of potential-generating filaments (the number of filaments: 24) made
of poly-L-lactic acid (PLLA) as a piezoelectric material was prepared (non-twisted
yarn) (optical purity (L-form) measured and calculated by high performance liquid
chromatography (HPLC): 99% or more, crystallinity measured by ultraX 18 manufactured
by Rigaku Corporation: 42 to 44%).
[0188] About 0.1 mL of a surface treating agent (NICEPOLE PR-99 (NICEPOLE series manufactured
by NICCA CHEMICAL CO., LTD.), an antistatic agent containing a PEG-modified polyester-based
polymer) was applied to that yarn and dried, and thus yarn F (non-twisted yarn) was
prepared (weight before application: 0.207 g, dry weight after application: 0.219
g, adhesion weight: 0.012 g, adhesion amount: 5.4% by weight).
Measurement of specific permittivity of yarn bundle of yarn F
[0189] A yarn bundle sample of the yarn F was prepared in the same manner as in Example
4 (see Fig. 11).
[0190] The yarn bundle sample (yarn F) was set in a jig (vise) and fixed with Kapton (registered
trademark) tape (see Fig. 12(A) (the photograph shows merely one example of a measurement
method, and the yarn contained in the yarn bundle sample is different from the yarn
F)).
[0191] In the same manner as in Example 4, the yarn bundle sample (yarn F) was disposed
to overlap (thickness: about 50 µm) between two circular measurement electrodes of
an LCR meter (Precision LCR Meter (model: E4980A) manufactured by Agilent Technologies,
Inc.) connected to a fixture (Dielectric Test Fixture (model: 16451B) manufactured
by Agilent Technologies, Inc.), and the yarn bundle sample was sandwiched and fixed
by the two measurement electrodes (see Fig. 12(B) (the photograph shows merely one
example of a measurement method, and the yarn contained in the yarn bundle sample
is different from the yarn F)).
[0192] In the case of this yarn bundle sample, since the surface treating agent was applied
to the yarn F, the filaments contained in the yarn gathered and a space was generated
between a yarn F and another yarn F.
[0193] In such a case, for example, a value obtained by subtracting the area of the space
from a value obtained by multiplying the sum of the areas S1 and S2 illustrated in
Fig. 13 by 4 (in other words, the value of the area in an ideal state) was calculated
as a sample area. The area of the space was calculated by actually measuring the interval
between a yarn F and another yarn F, preferably calculating the average of the total
gaps, and integrating over the width direction (the electrode diameter direction)
of the yarn bundle sample with a width of 1 cm arranged on a measurement electrode
(see Fig. 13).
[0194] As a result of measuring the specific permittivity of the yarn F over such a sample
area with the LCR meter, the value was about 4.5 (temperature: room temperature (25°C),
frequency: 1 kHz). Details of the measurement are shown in the following Table 4.
(Example 7)
Preparation of yarn G
[0195] A yarn composed of potential-generating filaments (the number of filaments: 24) made
of poly-L-lactic acid (PLLA) as a piezoelectric material was prepared (non-twisted
yarn) (optical purity (L-form) measured and calculated by high performance liquid
chromatography (HPLC): 99% or more, crystallinity measured by ultraX 18 manufactured
by Rigaku Corporation: 42 to 44%).
[0196] About 0.1 mL of a surface treating agent (SR-1800 (Water absorbent/SR agent series
manufactured by Takamatsu Oil & Fat Co., Ltd.), a surface treating agent containing
a polyester-based polymer and being capable of imparting water absorbency/SR property
(stain removability or anti-soiling property)/antistatic effect) was applied to that
yarn and dried, and thus yarn G (non-twisted yarn) was prepared (weight before application:
0.203 g, dry weight after application: 0.213 g, adhesion weight: 0.010 g, adhesion
amount: 4.7% by weight).
Measurement of specific permittivity of yarn bundle of yarn G
[0197] As a result of measuring the specific permittivity of the yarn G with an LCR meter
in the same manner as in the yarn F of Example 6, the value of the specific permittivity
was about 4.5. Details of the measurement are shown in the following Table 4.
(Example 8)
Preparation of yarn H
[0198] A yarn composed of potential-generating filaments (the number of filaments: 24) made
of poly-L-lactic acid (PLLA) as a piezoelectric material was prepared (non-twisted
yarn) (optical purity (L-form) measured and calculated by high performance liquid
chromatography (HPLC): 99% or more, crystallinity measured by ultraX 18 manufactured
by Rigaku Corporation: 42 to 44%).
[0199] About 0.1 mL of a surface treating agent (QUEENSTAT NW-E conc (QUEENSTAT series manufactured
by Kotani Chemical Industry Co., Ltd.), a surface treating agent containing a crosslinkable
hydrophilic urethane-based polymer and being capable of imparting water absorbency/SR
property (stain removability or anti-soiling property)/antistatic effect) was applied
to that yarn and dried, and thus yarn H (non-twisted yarn) was prepared (weight before
application: 0.205 g, dry weight after application: 0.234 g, adhesion weight: 0.029
g, adhesion amount: 12% by weight).
Measurement of specific permittivity of yarn bundle of yarn H
[0200] As a result of measuring the specific permittivity of the yarn H with an LCR meter
in the same manner as in the yarn F of Example 6, the value of the specific permittivity
was about 4.4. Details of the measurement are shown in the following Table 4.
(Example 9)
Preparation of yarn I
[0201] A yarn composed of potential-generating filaments (the number of filaments: 24) made
of poly-L-lactic acid (PLLA) as a piezoelectric material was prepared (non-twisted
yarn) (optical purity (L-form) measured and calculated by high performance liquid
chromatography (HPLC): 99% or more, crystallinity measured by ultraX 18 manufactured
by Rigaku Corporation: 42 to 44%).
[0202] About 0.1 mL of a liquid containing a metal oxide (titanium oxide (TiO
2) spray liquid (photocatalyst TiO2 antibacterial and deodorization spray available
from TRUSCO Nakayama Corporation)) was applied to that yarn and dried, and thus yarn
I (non-twisted yarn) was prepared (weight before application: 0.206 g, dry weight
after application: 0.207 g, adhesion weight: 0.001 g, adhesion amount: 0.48% by weight).
Measurement of specific permittivity of yarn bundle of yarn I
[0203] As a result of measuring the specific permittivity of the yarn I with an LCR meter
in the same manner as in the yarn F of Example 6, the value of the specific permittivity
was about 3.3. Details of the measurement are shown in the following Table 5.
(Example 10)
Preparation of yarn J
[0204] A yarn composed of potential-generating filaments (the number of filaments: 24) made
of poly-L-lactic acid (PLLA) as a piezoelectric material was prepared (non-twisted
yarn) (optical purity (L-form) measured and calculated by high performance liquid
chromatography (HPLC): 99% or more, crystallinity measured by ultraX 18 manufactured
by Rigaku Corporation: 42 to 44%).
[0205] About 0.1 mL of a liquid containing a metal oxide (titanium oxide (TiO
2) spray liquid (photocatalyst TiO
2 antibacterial and deodorization spray available from TRUSCO Nakayama Corporation))
was applied to that yarn and dried, and thus yarn J (non-twisted yarn) was prepared
(weight before application: 0.213 g, dry weight after application: 0.213 g, adhesion
weight: less than 0.001 g, adhesion amount: less than 0.47% by weight).
Measurement of specific permittivity of yarn bundle of yarn J
[0206] As a result of measuring the specific permittivity of the yarn J with an LCR meter
in the same manner as in the yarn F of Example 6, the value of the specific permittivity
was about 3.5. Details of the measurement are shown in the following Table 5.
[Table 3]
Yarn bundle sample |
Example 4 |
Example 5 |
Yarn |
D (Non-twisted yarn) |
E (Non-twisted yarn) |
Thickness [m] |
5.00E - 05 |
5.00E - 05 |
Cp [F] |
1.69E - 10 |
1.50E - 10 |
Area of electrode [m2] |
0.001134115 |
0.001134115 |
Area of sample [m2] |
0.000438149 |
0.000438149 |
Permittivity of vacuum |
8.85E - 12 |
8.85E - 12 |
Specific permittivity |
About 2.1 |
About 1.9 |
[Table 4]
Yarn bundle sample |
Example 6 |
Example 7 |
Example 8 |
Yarn |
F (Non-twisted yarn) |
G (Non-twisted yarn) |
H (Non-twisted yarn) |
Thickness [m] |
2.6E - 04 |
2.8E - 04 |
2.9E - 04 |
Cp [F] |
4.39E - 11 |
4.14E - 11 |
3.96E - 11 |
Area of electrode [m2] |
0.001134115 |
0.001134115 |
0.001134115 |
Area of sample [m2] |
0.000281082 |
0.000287416 |
0.000291216 |
Permittivity of vacuum |
8.85E - 12 |
8.85E - 12 |
8.85E - 12 |
Specific permittivity |
About 4.5 |
About 4.5 |
About 4.4 |
[Table 5]
Yarn bundle sample |
Example 9 |
Example 10 |
Yarn |
I (Non-twisted yarn) |
J (Non-twisted yarn) |
Thickness [m] |
9.0E - 05 |
1.0E - 04 |
Cp [F] |
1.44E - 10 |
1.39E - 10 |
Area of electrode [m2] |
0.001134115 |
0.001134115 |
Area of sample [m2] |
0.000438149 |
0.000438149 |
Permittivity of vacuum |
8.85E - 12 |
8.85E - 12 |
Specific permittivity |
About 3.3 |
About 3.5 |
Measurement of electric field intensity of electric field formed by yarns D to J
[0207] Since the yarns D to J contain PLLA (optical purity (L-form): 99% or more, crystallinity:
42 to 44%), it has been found that an electric field is generated by applying external
energy such as a tension or tensile strain of at least 0.15%. Furthermore, since the
yarns D to J have a specific permittivity of about 4.5 or less, the electric fields
formed by the yarns D to J were found to have an electric field intensity exceeding
about 0.1 V/µm as in the cases of the yarns A to C.
Antibacterial property
[0208] From the facts described above, the yarns D to J were found to have an electric field
intensity exceeding about 0.1 V/µm and exhibit a sufficient antibacterial property
against Trichophyton of about 10 µm.
[0209] As a result of measuring the specific permittivity of the yarn A of Example 1 and
the yarn B of Example 2 in the form of a yarn bundle in the same manner as the yarn
F of Example 6, the specific permittivity was about 1.4 with both the yarns, and there
were consistent with the results measured in Examples 1 and 2.
[0210] As a result of measuring the specific permittivity of the yarn C of Example 3 in
the form of a yarn bundle in the same manner as the yarn D of Example 4, the specific
permittivity of the yarn C was about 1.1, which was consistent with the result measured
in Example 3.
(Comparative Example 1)
[0211] Since the non-piezoelectric polylactic acid (PLA) polymer (TERRAMAC (registered trademark)
manufactured by Unitika Ltd., crystallinity: 34%) does not have piezoelectricity,
it has been found that the polymer does not generate charges and does not exhibit
antibacterial properties.
[0212] The above-described Examples 1 to 10 merely exemplify the yarn of the present disclosure,
and particularly merely exemplify that the specific permittivity, the generated potential,
and the like can be adjusted, and the yarn of the present disclosure is not limited
to the embodiments shown in the above-described Examples. While Examples 1 to 10 are
all directed to non-twisted yarns, by applying twist (for example, 45°), the electric
field intensity can be further increased and furthermore the antibacterial property
can be further enhanced.
[0213] Finally, aspects of the present invention will be additionally described. The invention
described above includes, but is not limited to, the following aspects.
(Aspect 1)
[0214] A yarn comprising a potential-generating filament or an electric field-forming filament,
wherein the yarn has a specific permittivity of 4.5 or less.
(Aspect 2)
[0215] The yarn according to Aspect 1, wherein the specific permittivity is 1.0 or more.
(Aspect 3)
[0216] The yarn according to Aspect 1 or 2, wherein the yarn has an impedance of 4.0 × 10
6 Ωm or more.
(Aspect 4)
[0217] The yarn according to Aspect 3, wherein the impedance is 1.8 × 10
7 Ωm or less.
(Aspect 5)
[0218] The yarn according to any one of Aspects 1 to 4, wherein the yarn has a resistivity
of 1.4 × 10
4 Ωm or more.
(Aspect 6)
[0219] The yarn according to Aspect 5, wherein the resistivity is 2.3 × 10
15 Ωm or less.
(Aspect 7)
[0220] The yarn according to any one of Aspects 1 to 6, wherein the potential-generating
filament comprises a piezoelectric material.
(Aspect 8)
[0221] The yarn according to Aspect 7, wherein the piezoelectric material comprises poly-L-lactic
acid (PLLA).
(Aspect 9)
[0222] The yarn according to Aspect 8, wherein the poly-L-lactic acid (PLLA) has a crystallinity
of 35% or more.
(Aspect 10)
[0223] The yarn according to any one of Aspects 1 to 9, wherein a dielectric is provided
on at least a part of a periphery of the potential-generating filament.
(Aspect 11)
[0224] The yarn according to Aspect 10, wherein the dielectric comprises an oil agent.
(Aspect 12)
[0225] The yarn according to Aspect 10 or 11, wherein the dielectric has conductivity.
(Aspect 13)
[0226] The yarn according to any one of Aspects 10 to 12, wherein the dielectric comprises
an antistatic agent.
(Aspect 14)
[0227] The yarn according to Aspect 10, wherein the dielectric comprises air.
(Aspect 15)
[0228] The yarn according to Aspect 10, wherein the dielectric comprises a polymer.
(Aspect 16)
[0229] The yarn according to Aspect 15, wherein the polymer comprises at least one selected
from the group consisting of ester-based polymers and urethane-based polymers.
(Aspect 17)
[0230] The yarn according to Aspect 10, wherein the dielectric comprises a metal oxide.
(Aspect 18)
[0231] The yarn according to Aspect 17, wherein the metal oxide is titanium oxide.
(Aspect 19)
[0232] The yarn according to any one of Aspects 1 to 9, wherein the yarn is free of a surface
treating agent.
(Aspect 20)
[0233] The yarn according to any one of Aspects 1 to 19, wherein the yarn is an antibacterial
yarn.
(Aspect 21)
[0234] A fabric comprising the yarn according to any one of Aspects 1 to 20.
[0235] The present invention can be used for various products. For example, the present
invention can be suitably used as a yarn or a fabric generally in daily products,
industrial products, and especially clothing products in which yarns are used.