BACKGROUND OF THE INVENTION
[0001] The present invention relates to non-woven fabrics having novel structures. An object
of the present invention is to provide new materials by using non-woven fabrics. The
present invention particularly relates to useful non-woven fabrics with unique three-dimensional
structures, wherein at least one junction portion is positioned in the internal portion
thereof.
[0002] Microorganism-fixing carriers made of non-woven fabrics on which microorganisms are
adhered and are allowed to propagate have heretofore been used for treating waste
water and as a microorganism reactor for industrial uses, as disclosed in Unexamined
Published Japanese Patent Application (Japan Kokai) Nos. 209787/1988, 229857/1989
and 38299/1991. The microorganism-fixing carriers made of non-woven fabrics have excellent
capacity for carrying microorganisms since the non-woven fabrics have porous structures.
However, they tend to be easily loaded due to the formation of a film of microorganisms
that are propagated, and thus a limitation is imposed on the amount of microorganisms
that can be carried. Furthermore, the contact area between the microorganisms and
the liquid, such as waste water that is to be treated by the microorganisms, is small.
[0003] As a microorganism-fixing carrier, there has been proposed a cord-like contact material
(Biocord™ manufactured by TBR Co., Japan) that employs braided cord technology. However,
the cord-like contact material is manufactured through complex manufacturing steps
with low productivity and at a high cost, without yielding large contact area. Moreover,
this material has a defect in that it tends to be easily deformed.
[0004] In an attempt to increase the amount of microorganisms that can be carried and to
increase the contact areas, the present inventors have studied the use of a cylindrical,
three-dimensional, non-woven fabric that is obtained by flatly or spirally winding
a non-woven fabric.
[0005] However, the cylindrical, three-dimensional, non-woven fabric obtained by winding
a sheet-like non-woven fabric has a weak tensile strength, and is broken or is deformed
when a strong tensile force is applied thereto during use of the fabric. Moreover,
the fibers that are chiefly oriented in the circumferential direction lack resistance
against compression. Besides, aerobic bacteria propagate only on the surface portion
of the non-woven fabric. Even when the non-woven fabric is obtained in a three-dimensional
form, therefore, the interior of the non-woven fabric is not sufficiently utilized,
making it difficult to increase the amount of microorganisms that are carried thereon
or to sufficiently increase the contact area with respect to the liquid to be treated.
[0006] There have further been proposed: (1) a spherical and solid non-woven fabric which
is obtained by packaging a fiber in a spherical mold and fixing it by using an adhesive
agent or with an adhesive fiber or by molding a bulky non-woven fabric or fiber webs
under the application of heat and pressure, followed by cutting the mold into a sphere;
and (2) a coupled bulky ball-like structure obtained by converging and fixing bundles
of bulky fibrous yarns at a predetermined interval, as disclosed in Unexamined Published
Japanese Patent Application (Japan Kokai) No. 27138/1991.
[0007] Like the aforementioned cylindrical three-dimensional non-woven fabrics, however,
these three-dimensional non-woven fabrics lack tensile strength, and are subject to
be broken or deformed when a strong tensile force is applied thereto during use. These
fabrics also fail to exhibit a restoring property after being compressed, and impose
limitations on the amount of carried microorganisms and on the contact areas.
[0008] Furthermore, a three-dimensional non-woven fabric has been desired even in other
fields for such uses as, for example, laces, ornamental products made of fibers, and
wadding. However, the cylindrical three-dimensional non-woven fabric obtained by winding
the non-woven fabric or the spherical three-dimensional non-woven fabric obtained
by packaging the non-woven fabric in the mold and fixing it by using an adhesive agent
or an adhesive fiber, still has weak tensile strength and is subject to be broken
or deformed when a strong tensile force is applied thereto during use. Such non-woven
fabrics have continuous surfaces that only slightly absorb external force, give hard
feeling to the touch, and are distorted upon bending. Moreover, the fibers that tend
to be oriented in the circumferential direction exhibit small resistance against the
compression and fail to restore the fabric to its initial shape after being compressed.
SUMMARY OF THE INVENTION
[0009] An object of the present invention is to provide a novel three-dimensional non-woven
fabric material manufactured by the use of a non-woven fabric. Particularly, an object
of present invention is to provide a three-dimensional non-woven fabric having excellent
tensile strength, advantageous resistance against compression, and a significantly
large surface area.
[0010] The present invention relates to a three-dimensional non-woven fabric having a junction
portion in the internal portion thereof. Further, the present invention relates to
three-dimensional non-woven fabric goods possessing at least one junction portion
in the internal portion thereof.
[0011] The present invention relates to a three-dimensional non-woven fabric having one
of various radial cross-sectional shapes and having a substantially linear or dot-like
junction portion in the internal portion thereof.
[0012] The present invention thus relates to a three-dimensional non-woven fabric having
a radial sectional shape that is continuous in the lengthwise direction. One embodiment
of the present invention relates to a non-woven fabric obtained by forming, and maintaining
a distance between, linear junction portions in a piece of starting non-woven fabric
or in a laminate of a plurality of layers of starting non-woven fabric, followed by
cutting the formed non-woven fabric at a position or along a line between one linear
junction portion and another linear junction portion. Another embodiment of the present
invention relates to a non-woven fabric obtained by forming dot-like junction portions
in a piece of starting non-woven fabric or in a laminate of a plurality of layers
of starting non-woven fabric, followed by cutting the formed non-woven fabric into
a desired shape so as to include the dot-like junction portion. According to the present
invention, a spherical three-dimensional non-woven fabric is obtained from a circular
starting non-woven fabric and, furthermore, three-dimensional non-woven fabrics of
a variety of shapes are obtained by changing the shape of the starting non-woven fabric.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Fig. 1 is a diagram illustrating a three-dimensional non-woven fabric of the present
invention in a step of production.
[0014] Fig. 2 is a partial perspective view illustrating the three-dimensional non-woven
fabric having a cross-sectional shape of petals according to the present invention.
[0015] Fig. 3 is a partial perspective view illustrating the three-dimensional non-woven
fabric in the shape of a cylinder according to the present invention.
[0016] Fig. 4 is a cross-sectional view illustrating the three-dimensional non-woven fabric
of the present invention in an embodiment where the distances from the junction portion
to the cutting line are different between the right side and the left side.
[0017] Fig. 5 is a cross-sectional view of the three-dimensional non-woven fabric of the
present invention when it is obtained by laminating starting non-woven fabrics having
different widths.
[0018] Fig. 6 is a diagram illustrating a three-dimensional non-woven fabric of the present
invention in a step of production.
[0019] Fig. 7 is a diagram illustrating a step for producing the three-dimensional non-woven
fabric of the present invention.
[0020] Fig. 8 is a cross-sectional view of a three-dimensional non-woven fabric of the present
invention.
[0021] Fig. 9 is a perspective view of a three-dimensional non-woven fabric of the present
invention.
[0022] Fig. 10 is a perspective view of a three-dimensional non-woven fabric of the present
invention.
[0023] Fig. 11 is a perspective view of a three-dimensional non-woven fabric of the present
invention.
[0024] Fig. 12 is a perspective view of a three-dimensional non-woven fabric of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The invention will now be described in detail with reference to specific embodiments
thereof.
[0026] The present invention provides a three-dimensional non-woven fabric having a radial
cross-sectional shape and having a junction portion in the internal portion thereof.
More particularly, the present invention provides a three-dimensional non-woven fabric
with a cross-sectional shape wherein said shape is continuous in the lengthwise direction
thereof. According to the present invention, furthermore, there is provided a method
of manufacturing a three-dimensional non-woven fabric by forming, and maintaining
a distance between, linear junction portions in a piece of starting non-woven fabric
or in a laminate of a plurality of pieces of starting non-woven fabric, followed by
cutting the formed non-woven fabric at a position or along a line between one linear
junction portion and another linear junction portion.
[0027] According to the present invention as shown in Fig. 1, there is obtained a three-dimensional
non-woven fabric having non-woven fabric pieces that are joined together at a junction
portion and having a radial cross-sectional shape by forming, and maintaining a distance
between, linear junction portions 2 in a piece of non-woven fabric 1 or in a laminate
of a plurality of pieces of non-woven fabric 1 in order to form a linear strongly
compressed portion in the non-woven fabric having a Predetermined thickness, followed
by cutting the formed non-woven fabric at a position or along a line between one linear
junction portion and another junction portion so that the non-woven fabric recovers
its thickness at the cut portion. When there exists a gap among the non-woven fabric
pieces, the three-dimensional non-woven fabric acquires the shape of petals in cross
section as shown in Fig. 2. When there is no gap, the three-dimensional non-woven
fabric acquires the cylindrical shape as shown in Fig. 3.
[0028] The linear junction portions 2 may be straight lines, undulated lines, solid lines,
broken lines or dotted lines which are spaced apart equally or unequally. The junction
portions can be formed, for example, by such sealing means as heat sealing, ultrasonic
sealing or high-frequency sealing; by adhesion means using an adhesive agent; or by
sewing means using a sewing machine or the like. The width of the junction portion
can be arbitrarily selected. When the sealing means or the adhesion means is employed,
however, preferably the linear junction portion has a width of from 1 to 5 mm. When
it is not allowed to use a thermoplastic fiber for constituting the non-woven fabric,
there should be employed the adhesion means or the sewing means. When it is allowed
to use a thermoplastic fiber, it is recommended to use the sealing means from the
standpoint of forming a junction portion having large tensile strength.
[0029] When it is intended to produce a three-dimensional non-woven fabric of a shape of
symmetrical petals in cross section or a cylindrical three-dimensional non-woven fabric
having a symmetrical shape in cross-section, the non-woven fabric should be cut at
the center line between the two linear junction portions. When it is intended to produce
a three-dimensional non-woven fabric of an asymmetrical shape in cross section, the
fabric should be cut at a position that is deviated toward either junction portion.
The cutting line 3 should preferably be a straight line but may be an undulated line
as required.
[0030] An embodiment of the manufacturing process according to the present invention will
now be described below in more detail.
[0031] One or a plurality of non-woven fabrics containing a heat-melting fiber are laminated
one upon another, so that the thickness (T, cm) of the laminate will become

with respect to the slit width, the slit width being the distance from one cutting
line through the junction portion to the second cutting line (W, cm). The thus set
non-woven fabric is, maintaining a predetermined distance, linearly and continuously
sealed (using heat, ultrasonic waves, or high-frequencies) or by sewing, followed
by cutting the sealed or stitched non-woven fabric into a product with a width W.
The non-woven fabric acquires the shape of petals in cross section when a relationship
between th thickness of the laminate and the width of the slit is 2T < π W. It acquires
the shape of a lace (circular) when the relationship is 2T ≧ π W. In this case, it
is desired to seal a laminate of a starting non-woven fabric having a cushioning property
and a starting non-woven fabric which is hard and broad.
[0032] The non-woven fabric including at least 20% or more, and preferably 35% or more,
of a heat-melting fiber and/or a heat-melting resin at the sealing portions exhibits
an increased strength. A wire may be inserted in the sealing portions in order to
further increase the strength.
[0033] The three-dimensional non-woven fabric has the following relations among the cross-sectional
shape, thickness of the laminate and the slit width:
(1) When the linear junction portion is positioned at the center of the slit width:
a. When 2T < π W, a gap exists among the non-woven fabric pieces, and the non-woven
fabric opens like petals. When 2T ≧ (from 1/3π W to 1/4π W), the petals open uniformly;
when 2T < (from 1/3 π W to 1/4 π W), the petals have a tendency to open nonuniformly.
b. When 2T ≧ π W, no gap exists among the non-woven fabric pieces, and the fiber layers
on the outer peripheral surfaces become continuous to acquire the shape of a lace.
When the thickness is further increased by compression during sealing, the lace may
be realized even when 2T < π W.
(2) When the linear junction portion is positioned at a portion other than the center
of the slit width: in the case where, as shown in Fig. 4, the distance from the cutting
line to one junction portion is long (as denoted by W1) and the distance from the
cutting line to another junction portion is short (as denoted by W2), the petals are
obtained on the side of the longer non-woven fabric pieces when T < π W1 and the lace
is obtained on the side of the shorter non-woven fabric pieces when T ≧ π W2.
[0034] The three-dimensional non-woven fabric having a linear junction portion in the internal
portion thereof of the present invention has a structure in which non-woven fabric
pieces are joined together at the linear junction portion as shown in Figs. 2 and
3, and exhibits excellent tensile strength.
[0035] The three-dimensional non-woven fabric has a structure in which non-woven fabric
pieces assemble together and the junction portion is at the internal linear portion
only, exhibiting excellent shape stability yet offering a surface that is soft to
the touch.
[0036] Moreover, even an external force that is exerted on the fabric is absorbed by the
non-woven fabric pieces that have a freedom of movement, and only little distortion
is left. Further, since the fibers are oriented along the non-woven fabric pieces,
the fibers, as a result, are oriented from the internal junction portion toward the
outside surface and exhibit excellent recovery against compression. Moreover, the
three-dimensional non-woven fabric has a structure in which the non-woven fabric pieces
assemble together and produce large surface areas. Therefore, for example, when the
three-dimensional non-woven fabric is used as a microorganism-fixing carrier, it carries
microorganisms in increased amounts, helps increase the chances of contact with the
liquid to be treated, and enables the reaction by the microorganisms to be efficiently
utilized.
[0037] As shown in Fig. 6, furthermore, the three-dimensional non-woven fabric that is adhered
at a dot-like junction portion may be obtained by forming a dot-like junction portion
2 in a piece of non-woven fabric 1 or in a laminate of a plurality of pieces of non-woven
fabric 1 to form a dot-like strongly compressed portion in the non-woven fabric having
a predetermined thickness, followed by permitting the non-woven fabric to recover
the thickness in the portions other than the dot-like junction portion. The result
is that a three-dimensional non-woven fabric is formed wherein non-woven fabric pieces
assemble together at the junction portion.
[0038] The non-woven fabric to be laminated may have any shape including, but not limited
to, a disk, an oval, a square, a polygon, a circle, a gourd, a dumbbell, a rectangle,
a parallelogram, a rhombus, a triangle, quadrilateral, an oblong, and the like. All
of the non-woven fabrics with various shapes can be put into practical use.
[0039] Referring to Fig. 7, the three-dimensional non-woven fabric of a spherical shape
is obtained when the non-woven fabrics of a circular shape are laminated and are joined
like a dot at the center of the circle.
[0040] In order to continuously manufacture the three-dimensional non-woven fabric, dot-like
junction points 2 are formed, while maintaining a distance therebetween in a piece
of long non-woven fabric 1 or in a laminate of a plurality of pieces of long non-woven
fabric 1 as shown in Fig. 7, followed by cutting the non-woven fabric 1 into a product
with a predetermined shape 3 (circular shape in Fig. 7) so as to include the dot-like
junction portion 2. Strongly compressed dot-like junction portions are sequentially
formed in the long non-woven fabric having a predetermined thickness, and the non-woven
fabric is sequentially punched into any shape such as a circular shape, an oval shape,
a square shape, a polygonal shape, a gourd shape, a dumbbell shape or the like so
as to include the dot-like junction portion, permitting the non-woven fabric to recover
its thickness at portions other than the dot-like junction portion. Such a process
allows for the continuous production of three-dimensional non-woven fabrics such as
the spherical non-woven fabrics as shown in Fig. 7, having non-woven fabric pieces
that are joined together at the dot-like junction portion.
[0041] Described next in more detail is an embodiment for producing a non-woven fabric that
is joined like a dot.
[0042] First, a piece of non-woven fabric or a laminate of a plurality of pieces of non-woven
fabric containing a heat-melting fiber is heat-sealed while being compressed and maintaining
a predetermined distance between the junction portions to form dot-like junction portions.
Then, the non-woven fabric is punched by using a circular punching mold with the dot-like
junction portion as a center of the circular sections. The portions other than the
dot-like junction portion recover the thickness of the non-woven fabric, so that the
non-woven fabric acquires a spherical three-dimensional shape.
[0043] The laminated non-woven fabric may be punched entirely, or the upper layer, the lower
layer, or both sides only of the laminate may be punched while leaving the central
portion.
[0044] Fig. 8 illustrates in vertical cross section the structure of the spherical three-dimensional
non-woven fabric in which non-woven fabric pieces are joined at the dot-like junction
portion. The non-woven fabrics closer to the upper and lower surfaces prior to being
joined together are greatly folded with the junction portion as a center. This spherical
non-woven fabric has a structure in which non-woven fabric pieces assemble together
and the junction portion is at the center of the sphere only. Therefore, the three-dimensional
non-woven fabric gives soft touch-feeling and excellent shape stability. Moreover,
even an external force that is exerted is absorbed since the non-woven fabric pieces
have freedom of movement, and only little distortion remains. Moreover, since the
fibers are oriented along the non-woven fabric pieces, the fibers tend to be oriented
from the center of the sphere toward the outer surface, and exhibit excellent recovery
against compression.
[0045] In the embodiment where the non-woven fabrics laminated first have a thickness T
and a circle that is cut has a radius r, there exists no gap among the non-woven fabric
pieces when T ≧ π r, and there exists a gap among the non-woven fabric pieces when
T < π r.
[0046] According to the present invention, there can be further obtained (1) a three-dimensional
non-woven fabric sheet (Fig. 9) having a linear junction portion and a plurality of
non-woven fabric pieces fixed at the linear junction portion; (2) a ring-like three-dimensional
non-woven fabric (Fig. 10) having a radial cross-sectional shape of radial and a ring-like
linear junction portion in the internal portion thereof; (3) a three-dimensional non-woven
fabric (Fig. 11) having a symmetrical cross-sectional shape with the linear junction
portion as an axis and having a radial cross-sectional shape; and (4) a three-dimensional
non-woven fabric (Fig. 12) having a linear junction portion in the internal portion
thereof and a sectional shape in which a plurality of loop-like non-woven fabric pieces
extend radially with the junction portion as a center.
[0047] The starting non-woven fabric may include, but is not limited to, natural fabrics,
synthetic fabrics and semi-synthetic fabrics. The starting non-woven fabric preferably
includes thermoplastic fibers. The synthetic and semi-synthetic fabrics may contain
synthetic organic or inorganic fibers. Preferably the non-woven fabric is selected
from the group consisting of a fiber manufactured from cotton, a polyolefin such as
polyethylene or polypropylene; a polyamide; an acrylate or methacrylate; a polyester
such as polyethylene terephthalate or polybutylene terephthalate; a polyvinyl chloride
or a polyvinylidene chloride; a styrene copolymer; a vinylpyridine copolymer; a composite
fiber such as a polyethylene/polypropylene composite fiber or a polyethylene terephthalate/polybutylene
terephthalate core-sheath composite fiber; and the like.
[0048] When the non-woven fabric includes adhesive components such as thermoplastic fibers,
the junction method may be such sealing means as ultrasonic sealing, high-frequency
sealing or heat sealing, and the sealing may be effected discretely when the non-woven
fabric is to be linearly joined.
[0049] When linearly joined, the sealing width can be any width but is preferably from about
1 to about 5 mm. When a large strength is required, the width of sealing should be
large. To reinforce the strength, a cord, a mesh or a knitted material may be inserted
in the sealing portion or on the whole surface, if desired.
[0050] When a thermoplastic fiber is used as the adhesive component in the non-woven fabric,
it is desired that the non-woven fabric is chiefly constituted by a polyolefin, a
polyester, a polyamide, a polyvinylidene chloride or an acrylic fiber.
[0051] A vinylon or a polyvinyl alcohol fiber can be sealed by the application of heated
steam and pressure. The sealing may be either in the vertical direction or in the
lateral direction.
[0052] The content ratio of the thermoplastic fiber varies depending upon the required tensile
strength, flexibility, width and thickness of the sealing portion, and the kind of
fiber that participates in the adhesion in the laminated non-woven fabric. It is,
however, desired that the ratio of the fiber that participates in the adhesion in
the non-woven fabric is at least 20% by weight or larger and, preferably, 40% by weight
or larger.
[0053] The sealing may be accomplished even when the ratio of the thermoplastic fiber is
smaller than 20% by weight. However, such sealing does not satisfy the requirements
of a large tensile strength and shape retaining property. However, this problem can
be solved when the non-woven fabric is sealed using a hot-melt adhesive or when a
cord or a knitted mesh is inserted as a reinforcing material.
[0054] Moreover, the linear junction portion can be formed relying upon the adhesion means
using an adhesive agent. In this case, the adhesive agent is applied, and the base
material is adhered while being compressed.
[0055] The adhesive agent for use in the present invention may include those that are capable
of strongly bonding the materials together or those that are capable of coupling two
faces together by a chemical force, by a physical force, or by a combination thereof.
Examples of the adhesive agent are preferably semi-synthetic high molecular weight
adhesive agents and synthetic high molecular weight adhesive agents including an unsaturated
aliphatic homopolymer or copolymer such as polyethylene, ethylene copolymer, polypropylene
or propylene copolymer, polyvinyl chloride, polyvinylidene chloride, copolymerizable
polyamide, copolymerizable polyester, vinyl acetate copolymer, acrylic resin, polyurethane,
epoxy resin, cellulose derivative, or the like. The adhesive agent may be of the composite-type.
[0056] The materials obtained according to the present invention may be used for any of
the applications where their properties can be utilized. For instance, the materials
can be used as a carrier for holding or immobilizing microorganisms, animal cells
and plant cells; as a material for polishing, brushing or cleaning; as a filter for
gases, liquids, gas-solid mixtures, liquid-solid mixtures and the like; for those
applications where water-absorbing property and oil-absorbing property are needed;
for insulating or for maintaining temperature; for applications where shock-buffering
property or cushioning property is required; for applications where advantageous visuality
is required; and for applications where abrasion resistance is required; etc.
[0057] Examples of the carrier include a microorganism-fixing (immobilizing) carrier for
purifying or cleaning water, a microorganism-fixing carrier for bioreactors, a microorganism-fixing
carrier for culture, artificial seaweeds, man-made gathering-place for fish and artificial
culture soil.
[0058] Examples of the three-dimensional non-woven fabric used for polishing, brushing and
cleaning include a scrubbing brush, a sponge, a brush for washing cars, and a household
brush.
[0059] Examples of the filter include a filter for trapping dirt and dust, a liquid filter,
an air conditioner filter, and a filter of a vacuum cleaner.
[0060] Examples of the draining material include water conduit, draining material for civil
engineering and the like.
[0061] Examples of the water-absorbing material include a water-absorbing pad, a dew-preventing
material, a pad for medical applications, sanitary napkin, and athletic articles.
Examples of the oil-absorbing material include an oil catcher, an oil fence and an
oil-absorbing material.
[0062] Examples of the heat insulating material include an arctic muffler, a substitute
for rope wound on trees, heat insulator for vehicles, and bedding are related products
including clothes such as pajamas.
[0063] Examples of the sound-absorbing material include a sound-absorbing material for ducts,
and sound-absorbing material for ships, automobiles and the like.
[0064] Examples of the shock-buffering material include corners, protectors and the like.
Examples of the cushioning material include wadding, cushion, pillow, back pad, shoulder
pad, etc. The non-woven fabric can be further used as ornamental products and toys
such as dolls, stuffed toys, lace, cushioned building blocks, etc.
[0065] Further described below are the applications, properties and shapes of the material.
When used as the microorganism-fixing (immobilizing) carrier for purifying or cleaning
water in order to decrease BOD, COD, nitrogen, phosphorus and the like in rivers,
lakes, ponds, sea and other places, the three-dimensional non-woven fabric has preferably
a cross-sectional shape of petals or a radially opened shape in cross-section. These
shapes help increase the surface areas of the carrier per a unit volume and increase
the chances of contact with microorganisms, dissolved oxygen, nutrient sources and
the like in the water. An increase in the surface area of the carrier permits aerobic
bacteria and microorganisms present in the water to adhere thereto to form a film
of microorganisms and helps increase the chances of contact between the film of microorganisms
and matter dissolved in the water such as oxygen, organic substances and nitrogen
compounds. As a result, due to the metabolism of aerobic bacteria in the presence
of oxygen, the organic substances and nitrogen compounds contained in the water turn
into microorganism body components, carbonic acid gas and water, so that the water
is purified. Usually, microorganisms contained in the water of rivers or in the waste
water to be treated spontaneously adhere to the microorganism-fixing (immobilizing)
carrier and propagate thereon. It is, however, also allowable to artificially adhere
microorganisms having particular functions in advance so that they will propagate.
[0066] When the cross-sectional diameter of the three-dimensional non-woven fabric used
for the microorganism-fixing carrier is too small, sufficient contact area is not
obtained. When the cross-sectional diameter of the three-dimensional non-woven fabric
is too large, the water does not sufficiently permeate up to the central portions.
Therefore, the cross-sectional diameter of the three-dimensional non-woven fabric
is preferably from about 2 to about 15 cm, and more preferably from about 3 to about
12 cm. The fiber composition used for the non-woven fabric is preferably selected
from the group consisting of a thermoplastic fiber manufactured from a polyolefin
such as a polyethylene or a polypropylene, a polyester, a polyamide, a polyvinyl chloride
or a polyvinylidene chloride. Such fibers may be used alone or in combination of two
or more kinds. In order to impart hydrophilic property and carbon source, the three-dimensional
non-woven fabric may contain non-thermoplastic fibers such as a viscose rayon, cotton
and the like. When the fineness of the fiber is too small, the non-woven fabric tends
to be easily loaded by the propagation of microorganisms; and when the fineness is
too large, the microorganisms tend to adhere less. It is therefore desired that the
fiber has the fineness of from about 5 to about 1000 denier, and more preferably from
about 10 to about 100 denier.
[0067] When the non-woven fabric used for the three-dimensional non-woven fabric has a too
great apparent density prior to forming the junction portion, the three-dimensional
non-woven fabric tends to be easily loaded. When the apparent density is too small,
however, the three-dimensional non-woven fabric loses shape stability. It is therefore
desired that the non-woven fabric has an apparent density within a range of from about
0.01 to about 0.2 g/cm³, and preferably within a range of from about 0.02 to about
0.1 g/cm³.
[0068] The non-woven fabric may be the one obtained by being adhered with a fiber, the one
obtained by being adhered with a binder, or the one obtained by mechanical entanglement.
There is no particular limitation in the method of production. From the standpoint
of strength and the like, however, it is desired to use the non-woven fabric obtained
by being adhered with the fiber or the non-woven fabric obtained by being adhered
with the binder. Furthermore, the non-woven fabric may be adhered with a polymer having
a microorganism-adsorbing function or may be imparted with an ion-exchanging ability
in order to increase the amount for fixing microorganisms and to quicken the adhesion
of microorganisms. When the three-dimensional non-woven fabric is used as the microorganism-fixing
carrier, the number of layers of the non-woven fabric to be laminated is preferably
from about 3 to about 6 (the number of non-woven fabric pieces is preferably from
about 6 to about 12), and each piece of non-woven fabric has preferably a thickness
of from about 3 to about 15 mm.
[0069] When it is desired to decrease the thickness of each non-woven fabric piece, to decrease
the number of non-woven fabric pieces and to evenly open the non-woven fabric pieces,
it is recommended to alternatingly laminate a thin, dense and wide non-woven fabric
4 and a thick, elastic and narrow nonwoven fabric 5, followed by linearly sealing
the central portions thereof as shown in Fig. 5. The three-dimensional non-woven fabric
of such a shape is particularly effective when it is desired to carry out the water
treatment using aerobic bacteria together with anaerobic bacteria. A film of aerobic
bacteria has a tendency to be easily formed on the peripheral open portions and a
film of anaerobic bacteria has a tendency to be easily formed on the central packaged
portions. Using the three-dimensional non-woven fabric of the present invention, it
is possible to control the gap among the non-woven fabric pieces. It is therefore
possible to provide a three-dimensional non-woven fabric having either an increased
region or a decreased region for forming the film of aerobic bacteria depending upon
the purifying conditions.
[0070] When used as a scrubbing brush or a polishing material, the three-dimensional non-woven
fabric must have cushioning property (repellent elasticity) and abrasion resistance
(particularly on the slit section). For this purpose, the non-woven fabric should
be one in which the ends of the fibers are exposed to the surfaces. The shape should
be such that the gap is small among the petals or that the petals abut with each other
forming a lace. Moreover, the slits may be meandered to realize a rugged cord-like
shape similar to that of a gourd. The fiber composition preferably consists of a polyamide,
a polyester, a polyolefin, a vinyl chloride or the like and the ingredients of the
composition are preferably each selected from material having high rigidity. In order
to increase the abrasion resistance, the non-woven fabric is preferably adhered by
using an adhesive agent in addition to being adhered with the heat-melting fiber.
The amount of the adhesive agent (inclusive of adhesive fiber) is preferably about
30% or larger, and the fineness is preferably from about 0.1 denier to about 100 denier,
though it may vary depending upon whether the non-woven fabric is used for coarse
polishing or finishing. Moreover, a polishing agent (e.g., carborundum, etc.) may
be applied thereto.
[0071] Touch feeling plays an important role when the three-dimensional non-woven fabric
is used for laces such as Christmas decoration, clothing (in which sealing portion
should be sewed, i.e., compressed and sewed by a sewing machine), mufflers, and accessories.
In this case, there should be no gap among the non-woven fabric pieces. The fiber
composition may be preferably a polyamide, a polyester, an acrylic fiber, a polyolefin,
a rayon, cotton, mixtures thereof and the like. The non-woven fabric preferably has
a fine structure as from about 0.1 to about 12 denier and should exhibit voluminous
feeling, soft touch-feeling and heat-insulating property by using a highly crimped
fiber and a latently crimped fiber in combination.
[0072] The present invention makes it possible to easily obtain long three-dimensional non-woven
fabrics having a large tensile strength and having a shape of petals or a radial shape
in cross-section, or three-dimensional non-woven fabrics of a ball-like shape or the
like having excellent touch-feeling and recovery property against compression, and
maintaining of fluffs in the fabric.
[0073] There is thus provided a material that can be used in a variety of applications.
In particular, the three-dimensional non-woven fabric of the present invention has
a large strength, excellent shape stability, and large surface area, thereby being
utilizable as a carrier for fixing or immobilizing microorganisms.
[0074] The following examples are intended to illustrate the invention in further detail
and should by no means be construed as limiting the scope of the present invention.
Example 1
[0075] Five pieces of a heat-bonding non-woven fabric comprising a polyethylene/polypropylene
composite fiber (ES fiber, fineness of 20 denier, produced by Chisso Co., Japan) each
having a weight of 200 g/m², a thickness of 8 mm and an apparent density of 0.025
g/cm³, are laminated, and linear sealing portions extending in the lengthwise direction
are formed by an ultrasonic sealing method maintaining a distance of 8 cm in the direction
of width. Both sides of the sealing portion are then slit in the lengthwise direction
maintaining a width of 4 cm on both sides at the sealing portion.
[0076] There is thus formed a three-dimensional non-woven fabric of a diameter of about
8 cm having 10 pieces of petals in cross-section, the inner peripheral portion being
intimately contacted and the outer circumferential portion being opened.
[0077] The cord-like three-dimensional non-woven fabric is cut to a length of one meter
and is used as a microorganism-fixing carrier for treating the water such as of ponds,
lakes, swamps, rivers, sea and the waste water from the factories. Because of its
large tensile strength and excellent recovering property against compression, the
three-dimensional non-woven fabric is very resistant to being broken or deformed.
The three-dimensional non-woven fabric has the shape of petals in cross-section and
a large surface area, and carries microorganisms in large amounts and possesses large
contact area with respect to the water.
Example 2
[0078] A halogenated benzyl-4-vinylpyridine styrene copolymer for adsorbing microorganisms
is adhered onto the base of the three-dimensional non-woven fabric of Example 1 to
prepare a non-woven fabric. Five pieces of the thus obtained non-woven fabric are
laminated in the same manner as in Example 1. The laminate is then sealed and slit
to obtain a three-dimensional non-woven fabric that exhibits excellent ability for
adsorbing microorganisms and is effectively used as a microorganism-fixing carrier.
Example 3
[0079] An acrylic adhesive agent is applied to a web of a polyamide fiber having a fineness
of 30 denier to prepare a non-woven fabric having a fiber/binder ratio of 60/40, a
weight of 350 g/m² and a thickness of 15 mm. Eight pieces of this non-woven fabric
are laminated, and are linearly sealed in the lengthwise direction by using a high-frequency
welder. The laminate is then slit, maintaining a width of 5 cm with the sealed portion
as a center. The laminated non-woven fabric expands like a circle in cross-section.
That is, there is obtained a three-dimensional non-woven fabric without gaps among
the non-woven fabric pieces and having high elasticity.
[0080] The non-woven fabric is cut into a length of one meter and is used as a substitute
for a sponge for washing the body, or is wrapped around the hand to be used as a brush
for washing a bath tub.
Example 4
[0081] A non-woven fabric is prepared by using a core-sheath composite fiber having a fineness
of 6 denier, and having a highly crimped core component of polyethylene terephthalate
and a sheath component of polybutylene terephthalate, the non-woven fabric having
a weight of 300 g/m² and a thickness of 25 mm. Four pieces of the thus obtained non-woven
fabric are laminated, compressed, and are sewed at ten places in the lengthwise direction
using a sewing machine, maintaining a distance of 6 cm. The laminate is then vertically
slit at portions midway among the sewed lines. There are simultaneously obtained 10
long non-woven fabrics of the form of a lace having a diameter of about 6 cm in cross-section.
This three-dimensional non-woven fabric offers soft touch-feeling, gives a high cushioning
property, and is effectively used for Christmas decorations, cushioning material for
clothing and winter laces.
Example 5
[0082] Five pieces of a heat-bonding non-woven fabric composed of a polyethylene/polypropylene
composite fiber (ES fiber, fineness of 20 denier, produced by Chisso Co., Japan) each
having a weight of 200 g/m², a thickness of 8 mm and an apparent density of 0.025
g/cm³, are laminated, and are sealed with ultrasonic waves like dots in the lengthwise
direction maintaining a distance of 3 cm. The laminate is then punched into a circle
of a radius of 1.5 cm with the dot-like sealed portion as a center to obtain a spherical
three-dimensional non-woven fabric.
[0083] When used as a microorganism-fixing carrier for treating the water such as from ponds,
lakes, swamps, rivers, sea and waste water from the factories, the spherical non-woven
fabric is only slightly subject to deformation. The non-woven fabric has a radial
cross-sectional shape and a large surface area, carries microorganisms in large amounts
and possesses a large contact area with respect to the water.
Example 6
[0084] A halogenated benzyl-4-vinylpyridine styrene copolymer for adsorbing microorganisms
is adhered onto the base of non-woven fabric of Example 5 to prepare a non-woven fabric.
Then, a spherical three-dimensional non-woven fabric is prepared in the same manner
as in Example 5. The spherical three-dimensional non-woven fabric exhibits excellent
ability for adsorbing microorganisms and is effectively used as a microorganism-fixing
carrier.
Example 7
[0085] An acrylic adhesive agent is applied to a web of a polyamide fiber having a fineness
of 30 denier to prepare a non-woven fabric having a fiber/binder ratio of 60/40, a
weight of 350 g/m² and a thickness of 15 mm. Ten pieces of this non-woven fabric are
laminated, and are sealed like dots in the lengthwise direction maintaining a distance
of 8 cm using an ultrasonic welder. The laminate is then punched in an oval shape
having a long diameter of 8 cm and a short diameter of 6 cm so that the dot-like sealed
portion is at the center, thereby to obtain a three-dimensional non-woven fabric without
gaps among the non-woven fabric pieces and having high elasticity.
[0086] The non-woven fabric can be used as a substitute for a sponge for washing the body,
or is wrapped around the hand to be used as a brush for washing a bath tub.
Example 8
[0087] A non-woven fabric is prepared by using a core-sheath composite fiber having a fineness
of 6 denier, and having a highly crimped core component of polyethylene terephthalate
and a sheath component of polybutylene terephthalate, the non-woven fabric having
a weight of 300 g/m² and a thickness of 25 mm. The non-woven fabric is cut into a
circle of a radius of 3 cm. Five pieces of the thus obtained circles are laminated,
compressed, and are joined at the center of the circle like a dot using a sewing machine.
There is obtained a spherical non-woven fabric having a diameter of about 6 cm in
cross-section. This three-dimensional non-woven fabric offers soft touch-feeling,
provides a high cushioning property, and is effectively used for Christmas decorations,
as cushioning material for clothing and the like.
Example 9
[0088] A halogenated benzyl-4-vinylpyridine styrene copolymer is adhered as a polymer for
adsorbing microorganisms onto a heat-bonding non-woven fabric of 50% by weight of
a polyester fiber having a fineness of 15 denier and 50% by weight of a polyester/low-melting
polyester composite fiber having a fineness of 15 denier, which has a weight of 250
g/m² and a thickness of 8 mm. The halogenated benzyl-4-vinylpyridine styrene copolymer
is adhered in an amount of 0.5% by weight with respect to the non-woven fabric. Three
pieces of the thus obtained non-woven fabric are laminated and are linearly sealed
in the lengthwise direction by the ultrasonic sealing method (sealing width of 4 mm)
and then, both sides of the sealed portion are slit in the lengthwise direction maintaining
a width of 4 cm on both sides.
[0089] There is obtained a long three-dimensional non-woven fabric having a diameter of
8 cm forming six non-woven fabric pieces in cross-section with the joined portion
as a center, the central portion being intimately contacted together and the outer
peripheral portion maintaining gaps among the non-woven fabric pieces.
[0090] The three-dimensional non-woven fabric is cut into a length of one meter. The thus
obtained three-dimensional non-woven fabrics are fixed into a frame of a metal or
a plastic material such that the long side (one meter long) is in the up-and-down
direction, maintaining a gap of 10 cm in the longitudinal and lateral directions,
in order to constitute a purification unit measuring 0.6 m deep, 9 m wide and 1 m
high.
[0091] River water having a BOD of 10 to 20 mg/liter is permitted to flow into the purification
unit at a flow rate of one liter/second to measure a decrease in the BOD through a
whole year. After having passed through the unit, the river water exhibits good quality
having a BOD of 5 mg/liter or smaller.
1. A three-dimensional non-woven fabric comprising one or more pieces of non-woven fabric
joined at at least one junction portion in the internal portion of said three-dimensional
non-woven fabric.
2. A three-dimensional non-woven fabric according to claim 1, wherein the at least one
junction portion is substantially linear.
3. A three-dimensional non-woven fabric according to claim 2, wherein the three-dimensional
non-woven fabric has a radial cross-sectional shape.
4. A three-dimensional non-woven fabric according to claim 3, wherein said shape is continuous
in the lengthwise direction.
5. A three-dimensional non-woven fabric according to claim 2, wherein said three-dimensional
non-woven fabric is in the form of a sheet.
6. A three-dimensional non-woven fabric according to claim 1, wherein said three-dimensional
non-woven fabric is in the form of a ring having a radial cross-sectional shape and
said at least one junction portion is a ring-like linear junction portion in the internal
portion of said three-dimensional non-woven fabric.
7. A three-dimensional non-woven fabric according to claim 2, wherein the three-dimensional
non-woven fabric has a cross-sectional shape symmetrical with the substantially linear
junction portion as an axis and has a radial cross-sectional shape in a cross-sectional
plane orthogonal thereto.
8. A three-dimensional non-woven fabric according to claim 2, wherein said three-dimensional
non-woven fabric has a cross-sectional shape of a plurality of loop-like non-woven
fabric pieces that radially extend in cross-section.
9. A three-dimensional non-woven fabric according to claim 4, wherein the three-dimensional
non-woven fabric is substantially of a form as shown in Fig. 2.
10. A three-dimensional non-woven fabric according to claim 5, wherein the three-dimensional
non-woven fabric is substantially of a form as shown in Fig. 9.
11. A three-dimensional non-woven fabric according to claim 6, wherein the three-dimensional
non-woven fabric is substantially of a form as shown in Fig. 10.
12. A three-dimensional non-woven fabric according to claim 7, wherein the three-dimensional
non-woven fabric is substantially of a form as shown in Fig. 11.
13. A three-dimensional non-woven fabric according to claim 8, wherein the three-dimensional
non-woven fabric is substantially of a form as shown in Fig. 12.
14. A three-dimensional non-woven fabric according to claim 1, wherein the at least one
junction portion is substantially a dot.
15. A three-dimensional non-woven fabric according to claim 14, wherein one or more pieces
of non-woven fabric of the same or similar shape are laminated and joined substantially
at one point.
16. A three-dimensional non-woven fabric according to claim 14, wherein the three-dimensional
non-woven fabric is substantially of a form as shown in Fig. 8.
17. A three-dimensional non-woven fabric according to claim 1, wherein the non-woven fabric
comprises at least one fiber selected from the group consisting of a polyethylene/polypropylene
composite fiber, or a polyethylene terephthalate/polybutylene terephthalate core-sheath
composite fiber, and a fiber manufactured from at least one compound selected from
the group consisting of polyolefin, polyamide, polyester, polyvinyl chloride, and
polyvinylidene chloride.
18. A method of producing a three-dimensional non-woven fabric comprising:
joining one or more pieces of a non-woven fabric to form one or more junction portions
in said fabric; and
cutting said fabric at a position between said junction portions.
19. A method of producing a three-dimensional non-woven fabric according to claim 18,
wherein at least one of said one or more junction portions is substantially linear.
20. A method of producing a three-dimensional non-woven fabric according to claim 18,
wherein at least one of said one or more junction portions is substantially a dot.
21. A method of producing a three-dimensional non-woven fabric according to claim 18,
wherein the junction portion is formed by heat sealing, ultrasonic sealing, high-frequency
sealing, by means of an adhesive agent or a yarn.
22. A method of producing a three-dimensional non-woven fabric according to claim 18,
wherein said cutting step comprises cutting said fabric along a straight line, a curved
line or a circle.
23. A method of producing a three-dimensional non-woven fabric according to claim 18,
wherein the junction portions are dot-like junction portions, and the non-woven fabric
is cut into any shape so as to include the dot-like junction portion.
24. A method of producing a three-dimensional non-woven fabric comprising joining one
or more pieces of a non-woven fabric having a circular shape by joining said fabric
at a dot-like junction portion at a center of the circular fabric.
25. A carrier comprising the three-dimensional non-woven fabric of claim 1.
26. A carrier according to claim 25, which is for carrying microorganisms.
27. A carrier according to claim 25, which is for treating waste water.