BACKGROUND
1. Technical Field
[0002] The present disclosure relates to equipment for manufacturing a fiber structure,
a method for manufacturing a fiber structure, and a fiber structure that are based
on a dry manufacturing technique in which as little water as possible is used. Such
a fiber structure is obtained by accumulating, through an air-laid process, defibrated
fibers in air to form a fibrous web. Such a fiber structure is used for, for example,
cushioning materials, packing materials, sound-absorbing materials, oil absorbers,
tablecloths, construction materials, heat-insulating materials, and recycled paper.
2. Related Art
[0003] In recent years, there have been proposed methods for manufacturing fiber structures
whose main components are wastepaper and that are thus reusable as materials after
being used and environmentally friendly. In addition, there have been provided methods
for stably and easily manufacturing, in a state of almost no environmental deterioration
due to dispersion of binders or paper dust, fiber structures in which wastepaper is
effectively used and that are, without stiffness caused by using water in the manufacturing
processes, excellent in, for example, shock absorbency, heat-insulating properties,
strength, and thermoformability.
[0004] JP-A-9-158024 discloses a fiber structure (a liquid absorber). The fiber structure is formed by
mixing and defibrating, in air, natural cellulose fibers and/or synthetic fibers,
a thermally fusible material, and a thickening material to form a mat, heating the
mat to a temperature equal to or higher than a melting point of the thermally fusible
material, and then fixing the thickening material in a fibrous web by compressing
the mat with press rolls.
[0005] In
JP-A-9-158024, fibers shift during formation with the press rolls, and thus the fiber orientations
become anisotropic. As a result, when the fiber structure is used, various desired
properties (for example, strength, shock absorbency, and absorption properties) may
not be achieved.
[0006] In addition, when variations in the distribution of fibers occur during accumulation
(air-laid processing) of the fibers, the variations may be increased by press-rolling
the fibers, and it is thus difficult to achieve dimensional accuracy in the thickness
direction of the fiber structure.
[0007] FIG. 8 is a schematic diagram illustrating a state in which the thermally fusible
material is melted through heating in a heating furnace 15 and compression with press
rolls 16 in JP-A-9-158024.
[0008] In
JP-A-9-158024, after the heating in the heating furnace 15, the mat is cooled from the surface
layers thereof before the density thereof increases. Thus, the concentration of the
thermally fusible material in the vicinities of an upper surface sheet 3 and a bottom
surface sheet 4 is lower than that at the center in the thickness direction. As a
result, the adhesive strength between the mat and the upper surface sheet 3 and between
the mat and the bottom surface sheet 4 may be low.
[0009] After the mat is removed from the heating furnace 15, the surface layers of the mat
harden during transportation, and the inside of the mat then cools. Thus, the ratio
of the melted component on the mat surface adhering to the upper surface sheet 3 and
the mat surface adhering to the bottom surface sheet 4 is low, resulting in low adhesive
strength. For this reason, the mat and the upper surface sheet 3 and/or the bottom
surface sheet 4 do not sufficiently adhere to each other.
[0010] When the adhesive strength between the mat and the upper surface sheet 3 and/or the
bottom surface sheet 4 is low, the mat and the upper surface sheet 3 and/or the bottom
surface sheet 4 may separate during cutting of pieces from the whole fiber structure.
Alternatively, the upper surface sheet 3 or the bottom surface sheet 4 may peel from
the mat during handling, and the fiber structure may thus be difficult to orderly
store or insert into a container or a case, or post-processing may be difficult to
perform.
SUMMARY
[0011] Equipment for manufacturing a fiber structure according to an aspect of the present
disclosure includes: a defibrating section configured to pulverize and defibrate a
fiber material containing fibers; a transport section through which a defibrated material
defibrated by the defibrating section is transported; a melting-material mixing section
configured to mix a melting material into the defibrated material transported through
the transport section; a fibrous-web forming section configured to accumulate the
defibrated material in which the melting material is mixed and form a fibrous web;
a sheet supply section configured to supply a shape-maintaining sheet to the fibrous
web; and a heating-and-compression mechanism configured to compress the shape-maintaining
sheet and the fibrous web between planar plates and heat the shape-maintaining sheet
and the fibrous web to a temperature equal to or higher than a temperature at which
the melting material softens.
[0012] In the equipment for manufacturing a fiber structure, the sheet supply section supplies
the shape-maintaining sheet to a first surface and a second surface opposite to the
first surface of the fibrous web.
[0013] In the equipment for manufacturing a fiber structure according to an aspect of the
present disclosure, the melting material is melting-resin fibers, and the melting-resin
fibers have a fiber fineness of 0.5 dtex or more and 2.0 dtex or less.
[0014] In the equipment for manufacturing a fiber structure according to an aspect of the
present disclosure, the melting material is resin particles, and the resin particles
have a volume average particle diameter of 4 µm or more and 20 µm or less.
[0015] The equipment for manufacturing a fiber structure according to an aspect of the present
disclosure further includes a functional-material mixing section configured to mix
a functional material into the defibrated material.
[0016] In the equipment for manufacturing a fiber structure according to an aspect of the
present disclosure, the functional material is a fire-retardant material.
[0017] In the equipment for manufacturing a fiber structure according to an aspect of the
present disclosure, the fibrous-web forming section includes a dispersion member configured
to disperse the defibrated material, a mesh belt on which the dispersed defibrated
material is accumulated, the mesh belt being configured to transport the accumulated
defibrated material, and a suction member configured to suction the dispersed defibrated
material via the mesh belt.
[0018] The equipment for manufacturing a fiber structure according to an aspect of the present
disclosure further includes a liquid atomizer configured to atomize a liquid onto
the fibrous web transported by a mesh belt.
[0019] A method for manufacturing a fiber structure according to an aspect of the present
disclosure includes: pulverizing and defibrating a fiber material containing fibers;
transporting a defibrated material through a transport section; mixing a melting material
into the defibrated material transported through the transport section; accumulating
the defibrated material in which the melting material is mixed and forming a fibrous
web; supplying a shape-maintaining sheet to the fibrous web; and compressing and heating
the fibrous web to which the shape-maintaining sheet is supplied and melting the melting
material.
[0020] In the method for manufacturing a fiber structure, the supplying of the shape-maintaining
sheet includes supplying the shape-maintaining sheet to a first surface and a second
surface opposite to the first surface of the fibrous web.
[0021] A method for manufacturing a fiber structure according to an aspect of the present
disclosure includes: pulverizing and defibrating a fiber material containing fibers;
transporting a defibrated material through a transport section; mixing a melting material
into the defibrated material transported through the transport section; napping a
surface of a first shape-maintaining sheet; accumulating, on the surface of the first
shape-maintaining sheet, the defibrated material in which the melting material is
mixed and forming a fibrous web; supplying a second shape-maintaining sheet on an
opposite side of the fibrous web from a side on which the first shape-maintaining
sheet is disposed; and compressing and heating the fibrous web disposed between the
first shape-maintaining sheet and the second shape-maintaining sheet and melting the
melting material.
[0022] In the method for manufacturing a fiber structure, the mixing of the melting material
includes mixing, as the melting material, melting-resin fibers having a fiber fineness
of 0.5 dtex or more and 2.0 dtex or less into the transported defibrated material.
[0023] A fiber structure according to an aspect of the present disclosure is manufactured
by the method for manufacturing a fiber structure.
[0024] As described above, in the equipment and the method for manufacturing a fiber structure
in the present disclosure, the fibrous web to which the shape-maintaining sheets are
supplied is simultaneously heated and compressed to adhere the shape-maintaining sheets
to the fibrous web. Thus, it is possible to manufacture a fiber structure whose strength
and rigidity are maintained and that has great ease of handling without, for example,
losing the shape.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025]
FIG. 1 is a schematic diagram illustrating a schematic configuration of equipment
for manufacturing a fiber structure according to an embodiment of the present disclosure.
FIG. 2 is a schematic diagram of a fiber structure yet to be subjected to heating
and compression.
FIG. 3 is a schematic diagram of a fiber structure according to the embodiment of
the present disclosure.
FIG. 4 is a schematic diagram illustrating heating and compression according to the
embodiment of the present disclosure and a state in which a melting material is melted.
FIG. 5 illustrates an outline of a peeling test method.
FIG. 6 illustrates peeling test results.
FIG. 7 is a schematic diagram illustrating a schematic configuration of equipment
for manufacturing a fiber structure according to another embodiment of the present
disclosure.
FIG. 8 is a schematic diagram illustrating a state in which a thermally fusible material
is melted through heating in a heating furnace and compression with press rolls in
the related art.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0026] Embodiments of the present disclosure will be described below with reference to the
drawings. FIG. 1 is a schematic diagram illustrating a schematic configuration of
equipment for manufacturing a fiber structure according to an embodiment of the present
disclosure. The equipment for manufacturing a fiber structure according to the embodiment
is based on a technique in which a sheet material OP (for example, wastepaper) containing
fibers is recycled into a new fiber structure product through a dry process in which
as little water as possible is used.
[0027] A manufactured fiber structure is also usable for sound-absorbing materials, which
absorb sound, and cushioning materials (packing materials), which absorb external
shock. By disposing the fiber structure functioning as a sound-absorbing material
inside, for example, various home appliances, the fiber structure can reduce leakage
of operating noise to the outside of the appliances. In addition to home appliances,
the fiber structure is also usable for various construction materials or sound-absorbing
materials to be disposed in, for example, concert halls to control acoustics.
[0028] Corrugated cardboard or newspaper is also usable for the sheet material OP (for example,
wastepaper) containing fibers, which is supplied to the equipment for manufacturing
a fiber structure according to the embodiment. However, office wastepaper whose recycling
routes are yet to be sufficiently established such as confidential document wastepaper
or general wastepaper of A4 size, which is currently widespread in most offices, is
intended to be used for the sheet material OP. When such a sheet material OP (for
example, wastepaper) containing fibers is supplied to a coarse crusher 10 of the equipment
for manufacturing a fiber structure, the sheet material OP containing fibers is cut
into paper pieces of several centimeters square by coarse crushing blades 11 of the
coarse crusher 10. In addition, it is preferable to provide, to such a coarse crusher
10, an automatic feed mechanism 5 for continuously supplying the sheet material OP
containing fibers. In consideration of productivity, the supply rate in the automatic
feed mechanism 5 is preferably high.
[0029] The coarse crushing blades 11 of the coarse crusher 10 may be a device whose cutting
width is wider than the blades of a common shredder. Coarsely crushed pieces (paper
pieces) cut into several centimeters square by the coarse crushing blades 11 may be
led to a defibrating process, which is a subsequent process, via a metering feeder
50, a hopper 12, and an inlet pipe 20 for coarsely crushed pieces (paper pieces).
[0030] The metering feeder 50 may use any method as long as a fixed amount of coarsely crushed
pieces (paper pieces) are supplied to a defibrator, and a vibrating feeder is suitable
for the metering feeder 50.
[0031] Such a vibrating feeder tends not to transport a constant amount of light coarsely
crushed pieces (paper pieces) due to, for example, static electricity. Thus, light
coarsely crushed pieces (paper pieces) are preferably formed into a block-like shape
by multi-feeding with the coarse crusher 10 in the previous process. Each block weight
is preferably 0.5 g to 2 g.
[0032] Coarsely crushed pieces (paper pieces) may be continuously supplied from the coarse
crusher 10 to the vibrating feeder or may be stored in flexible containers and then
supplied to the vibrating feeder. In this case, flexible containers function as buffers,
and thus it is possible to reduce the influence, on the manufacturing equipment, of
fluctuations in the amount of collected wastepaper to be the sheet material OP. The
amount of coarsely crushed pieces (paper pieces) supplied from flexible containers
is preferably equal to the amount of coarsely crushed pieces (paper pieces) with which
the fiber structure can be continuously produced for about one hour, depending on
the production amount of the fiber structure. A large amount of coarsely crushed pieces
(paper pieces) supplied from flexible containers to the vibrating feeder at the same
time may influence vibration of the vibrating feeder, and thus it is preferable to
gradually supply coarsely crushed pieces (paper pieces) from flexible containers.
Examples of a method for gradually supplying coarsely crushed pieces (paper pieces)
from flexible containers can include a method in which flexible containers are inclined,
a method in which flexible containers are shaken by, for example, a motor, and a method
in which flexible containers are partly pierced using an air cylinder.
[0033] The inlet pipe 20 for coarsely crushed pieces (paper pieces) is in communication
with an inlet 31 of a dry defibrator 30, and the coarsely crushed pieces (paper pieces)
led into the dry defibrator 30 from the inlet 31 are defibrated between a rotating
rotor 34 and a stator 33 and are formed into defibrated fibers DF. The dry defibrator
30 is a mechanism that generates airflow, and the defibrated fibers DF defibrated
in, for example, air are led by such airflow from an outlet 32 to a transport pipe
40.
[0034] Hereinafter, a specific example of the dry defibrator 30 is described. For example,
dry wastepaper defibrators including a disc refiner, a turbo mill (produced by FREUND-TURBO
CORPORATION), a Ceren Miller (produced by MASUKO SANGYO CO., LTD), or a wind generating
mechanism such as that disclosed in
JP-A-6-93585 are usable for the dry defibrator 30. The size of the coarsely crushed pieces (paper
pieces) supplied to such a dry defibrator 30 may be equal to the size of paper pieces
discharged from a common shredder. In consideration of the strength of a manufactured
fiber structure, preferably, the coarsely crushed pieces (paper pieces) have a long
fiber length. However, excessively large coarsely crushed pieces (paper pieces) are
difficult to supply to the dry defibrator 30. Thus, the size of the coarsely crushed
pieces (paper pieces) discharged from the coarse crusher 10 is preferably several
centimeters square.
[0035] In the dry defibrator 30 including a wind generating mechanism, coarsely crushed
pieces (paper pieces) are suctioned, by using the airflow generated by the dry defibrator
30, from the inlet 31 together with the airflow and are defibrated and transported
toward the outlet 32. The dry defibrator 30 defibrates supplied coarsely crushed pieces
(paper pieces) into a flocculent form.
[0036] For example, an Impeller Mill 250 (produced by Seishin Enterprise Co., Ltd.), which
is a type of turbo mill, can generate an airflow having an airflow volume of about
3 m
3/min at 8000 rpm (peripheral speed of about 100 m/s) by using 12 blades installed
at a part closer to the outlet thereof. In this case, the airflow velocity at a part
closer to the inlet 31 is about 4 m/s, and coarsely crushed pieces (paper pieces)
are led into the dry defibrator 30 by the airflow. The coarsely crushed pieces (paper
pieces) led into the dry defibrator 30 are defibrated between the blades rotating
at high velocity and the stator 33 and are discharged from the outlet 32. The discharge
velocity is about 6.5 m/s with a discharge pipe diameter of ϕ100.
[0037] When the dry defibrator 30 does not include a wind generating mechanism, it is sufficient
to separately provide, for example, a blower configured to generate airflow that leads
coarsely crushed pieces (paper pieces) into the inlet 31.
[0038] In the defibrating process in the dry defibrator 30, it is preferable to defibrate
pulp into a fibrous form in which the shape of coarsely crushed pieces (paper pieces)
is lost because unevenness of the fiber structure to be formed in a subsequent process
is eliminated. In this process, for example, printed ink or toner, and coating and
additive materials for paper (papermaking chemicals), such as a bleed prevention agent,
are also pulverized into grains of several tens of micrometers or less (hereinafter
referred to as ink grains and papermaking chemicals). Thus, the output from the dry
defibrator 30 is fibers (defibrated fibers DF), ink grains, and papermaking chemicals
obtained by defibrating coarsely crushed pieces (paper pieces).
[0039] For example, when a disc refiner is used as the dry defibrator 30, it is preferable
to form stationary blades at the circumferential edge thereof in addition to the rotary
blades formed on a disc-shaped surface thereof in the radial direction. The gap between
the rotary blades on the rotor 34 and the stationary blades on the stator 33 is preferably
kept to about the thickness of a paper piece, for example, about 100 to 150 µm. In
this case, the defibrated material is moved to the outer circumference by the airflow
generated by the rotary blades and is discharged from the outlet 32.
[0040] The defibrated material (defibrated fibers DF) discharged from the dry defibrator
30 (ϕ100, sectional area of about 78 cm
2) is led into a fibrous-web forming machine 100 through the transport pipe 40 and
a transport pipe 60.
[0041] A melting-material transport pipe 61 branches off from the transport pipe 60. The
amount of a melting material supplied from a hopper 13 for melting materials (melting-resin
fibers) is controlled by a melting-material control valve 65. The melting material
is supplied to the transport pipe 60 via the melting-material transport pipe 61 and
can be mixed into the defibrated fibers DF transported through the transport pipe
60. The accuracy of the amount of a melting material to be transported can be increased
by a method in which the opening degree of the valve is controlled by measuring, with
a scale on which a feeder is placed, a reduced amount of the melting material.
[0042] The pipe diameter of the melting-material transport pipe 61 is preferably smaller
than the pipe diameter of the transport pipe 60. This is because melting-resin fibers
that are a melting material are likely to disperse in airflow due to increased airflow
velocity.
[0043] The melting material maintains the strength and the rigidity of the fiber structure
as a formed product formed by the defibrated fibers DF and prevents dispersion of
paper dust and fibers. The melting material is melted by being added to the defibrated
fibers DF and being heated to bind the fibers. The melting material may be any material,
such as fibrous materials or powder (particle or granular) materials, as long as the
material is melted by a heating process. However, materials that melt at 200°C or
lower are preferable because, for example, paper yellowing does not occur. Materials
that melt at 160°C or lower are more preferable in terms of energy.
[0044] The melting material preferably contains a thermoplastic resin, which melts during
heat forming. More preferably, fibrous melting materials, which are easily intertwined
with defibrated cotton fibers, are used to produce low-density products. It is more
preferable to use composite fibers having a core-in-sheath structure. Melting materials
having a core-in-sheath structure are preferable because a sheath portion exhibits
an adhesive function when melted at a low temperature and because a core portion remains
in a fiber form, that is, the shape of the core portion is maintained. It is preferable
to use, for example, ETC and INTACK series, which are produced by ES FIBERVISIONS,
Inc., or Tetoron (registered trademark), which is a polyester fiber for dry nonwoven
fabric and is produced by TEIJIN LIMITED.
[0045] The fineness of each melting-resin fiber is preferably 0.5 dtex or more and 2.0 dtex
or less. When the fineness of each melting-resin fiber is more than 2.0 dtex, it is
not possible to achieve sufficient adhesive strength between a first shape-maintaining
sheet (or a second shape-maintaining sheet) and a defibrated-cotton sheet (fibrous
web). When the fineness of each melting-resin fiber is less than 0.5 dtex, for example,
there may arise problems in that, in terms of fiber manufacture, the position of a
core deviates from the center of a sheath in a core-in-sheath structure and the fibers
are difficult to discharge linearly. In addition, there may arise a problem in that,
because the fineness of each melting-resin fiber is smaller than that of each of the
defibrated fibers DF, the melting-resin fibers and the defibrated fibers DF are mixed
unevenly during the manufacturing process due to a large effect of static electricity.
[0046] The length of each melting-resin fiber is preferably about 1 to 10 mm. When the length
of each melting-resin fiber is smaller than 1 mm, it is difficult to maintain the
shape of the fiber structure due to insufficient adhesive strength. When the length
of each melting-resin fiber is larger than 10 mm, fibers are formed into balls in
airflow, resulting in a deterioration in the dispersiveness of the fibers.
[0047] Below the melting-material transport pipe 61, which branches off from the transport
pipe 60, a functional-material transport pipe 62 branches off from the transport pipe
60. Powder fire retardants are preferably usable in the product. The amount of a fire
retardant as a functional material supplied from a hopper 14 for functional materials
(fire retardants) is controlled by a functional-material control valve 66. The fire
retardant is supplied to the transport pipe 60 via the functional-material transport
pipe 62. In the transport pipe 60, the fire retardant can be mixed into the defibrated
fibers DF, into which a melting material is mixed, during transportation. The accuracy
of the amount of a fire retardant to be transported can be increased by a method in
which the opening degree of the valve is controlled by measuring, with a scale on
which a feeder is placed, a reduced amount of the fire retardant.
[0048] The pipe diameter of the functional-material transport pipe 62 is preferably smaller
than the pipe diameter of the transport pipe 60. This is because a functional material
is likely to disperse in airflow due to increased airflow velocity.
[0049] The fire retardant is added to impart incombustibility to the defibrated-cotton sheet
(fibrous web) formed by the defibrated fibers DF. For example, hydroxides such as
aluminum hydroxide and magnesium hydroxide, boric acid, boric acid compounds such
as ammonium borate, phosphorus-based organic materials containing, for example, ammonium
polyphosphate or phosphoric esters, or nitrogenous compounds such as melamine and
isocyanurate are usable for the fire retardant. In particular, it is preferable to
use a composite containing melamine and phosphoric acid.
[0050] Preferably, the fire retardant is a solid fire retardant. The volume average particle
diameter of the solid fire retardant is preferably 1 µm or more and 50 µm or less.
When the volume average particle diameter is less than 1 µm, it is difficult to transport
the solid fire retardant by airflow when the solid fire retardant is accumulated as
a defibrated-cotton sheet (fibrous web) (S) in a subsequent suction process. When
the volume average particle diameter is more than 50 µm, the adhesive power of the
solid fire retardant to fibers is reduced, and thus the solid fire retardant is likely
to fall off the fibers. As a result, the solid fire retardant is distributed unevenly
and cannot provide sufficient fire retardancy.
[0051] The defibrated fibers DF, into which a melting material and a functional material
are mixed through the transport pipe 60, is led into the fibrous-web forming machine
100.
[0052] The first shape-maintaining sheet (N
1) is supplied from a first-shape-maintaining-sheet supply roller 81 to the fibrous-web
forming machine 100. The first shape-maintaining sheet (N
1) to be supplied from the first-shape-maintaining-sheet supply roller 81 is a base
of a bottom surface (first surface) of the defibrated-cotton sheet (fibrous web) formed
by the fibrous-web forming machine 100.
[0053] Both woven fabric and nonwoven fabric are usable for the first shape-maintaining
sheet (N
1) in the present disclosure as long as the sheet can maintain the shape of the fibrous
web by supporting the fibrous web. The first shape-maintaining sheet (N
1) is required to also have air permeability to properly accumulate the defibrated
material, the melting material, and the functional material on which the airflow generated
by a suction device 110 acts via the first shape-maintaining sheet (N
1) and that are mixed on the first shape-maintaining sheet (N
1). The additives in wastepaper and the print ink grains pulverized by the dry defibrator
30 are removed from the mixed defibrated material through the suction process. The
size of each opening in the first shape-maintaining sheet (N
1) is preferably 100 µm or less. The first shape-maintaining sheet (N
1) is an exterior portion of the product and may thus be colored. In the embodiment,
ecule (registered trademark) 3151A, which is a polyester filament nonwoven fabric
manufactured through spunbonding by TOYOBO CO., LTD., is used for such a first shape-maintaining
sheet (N
1) having air permeability.
[0054] The fibrous-web forming machine 100 is described schematically. The fibrous-web forming
machine 100 includes mainly a dispersion mechanism configured to uniformly disperse
defibrated fibers in, for example, air, and a mechanism configured to suction the
dispersed defibrated fibers onto a mesh belt 122.
[0055] The dispersion mechanism includes a forming drum 101. The mixed defibrated material
and a mixed gas (mixed air) are simultaneously supplied to the rotating forming drum
101. A small-hole screen is disposed on a surface of the forming drum 101. The defibrated
fibers DF, into which a melting material and a functional material are mixed, are
discharged from the small-hole screen. The hole diameter of the drum mesh (hole diameter
of the small-hole screen) depends on the size of the mixed defibrated material, and
the shape of the hole may be a circular shape. Preferably, each hole is an elongated
hole of about 5 mm × 25 mm to achieve both productivity and uniformity.
[0056] A defibrated material, a melting material, and a functional material are uniformly
mixed with a mixed gas (mixed air) and pass through the holes in the forming drum
101.
[0057] Current plates capable of adjusting the uniformity of materials in the width direction
are disposed below the forming drum 101. The mesh belt 122, which is endless and on
which the mesh stretched between tension rollers 121 is formed, is disposed below
the current plates. A transport gas (transport air) and a mixed gas (mixed air) are
suctioned via a suction box. When the amount of a suction gas is larger than the sum
of the amount of a transport gas and the amount of a mixed gas, it is possible to
prevent materials and paper dust generated during defibration from being blown off.
Fine powders (waste powders) passing through the first shape-maintaining sheet (N
1) and the mesh belt 122 are mixed in the suction gas. Thus, to separate the fine powders
(waste powders), it is preferable to dispose, downstream of the process, a cyclone
or a filter dust collector.
[0058] Below the fibrous-web forming machine 100 as a fiber-structure forming machine, the
mesh belt 122 is moved in the directions of arrows in FIG. 1 by at least one of the
tension rollers 121 being driven to rotate. For example, the dirt on a surface of
the mesh belt 122 is removed with a cleaning blade 123, which is in contact with the
mesh belt 122. The mesh belt 122 may be cleaned by air.
[0059] The mesh belt 122 may be made of any material, such as metal or resin, as long as
a sufficient amount of suction air is able to pass through the mesh belt 122 and as
long as the mesh belt 122 has sufficient strength to hold materials. When the hole
diameter of the mesh is excessively large, a surface of the defibrated-cotton sheet
(fibrous web) (S) is formed into an uneven shape. Thus, the hole diameter of the mesh
is preferably about 60 µm to 125 µm. When the hole diameter of the mesh is less than
60 µm, it is difficult for the suction device 110 to generate stable airflow.
[0060] The first shape-maintaining sheet (N
1) is supplied onto the mesh belt 122 from the first-shape-maintaining-sheet supply
roller 81 at a moving velocity identical to the moving velocity of the mesh belt 122.
The suction device 110 can be formed by forming an airtight box having a desirably
sized window under the mesh belt 122 and by suctioning gas (for example, air) from
a part of the box other than the window to evacuate the box.
[0061] With such a configuration, the defibrated fibers DF transported through the transport
pipe 60 are led into the fibrous-web forming machine 100 for forming the fiber structure.
The defibrated fibers DF pass through the small-hole screen on the surface of the
forming drum 101 and accumulate on the first shape-maintaining sheet (N
1) on the mesh belt 122 due to the suction force generated by the suction device 110.
In this case, the fibrous web can be formed by accumulating the defibrated fibers
DF having a uniform sheet-like shape on the first shape-maintaining sheet (N
1) while the mesh belt 122 and the first shape-maintaining sheet (N
1) move. The accumulated material (fibrous web) (S) formed by accumulating the defibrated
fibers DF is heated and compressed to form the fiber structure having a sheet-like
shape.
[0062] The amount of the defibrated fibers DF to be accumulated and the density of the fiber
structure to be completed through a subsequent pressing process are determined in
the fibrous-web forming machine 100. The defibrated fibers DF are accumulated to a
height of about 40 to 60 mm to obtain a fiber structure having, for example, a thickness
of 10 mm and a density of about 0.1 to 0.15 g/cm
3.
[0063] In the embodiment, to mix melting-resin fibers and a fire retardant into the defibrated
fibers DF during transportation through the transport pipe 60, the melting-material
transport pipe 61 and the functional-material transport pipe 62, which supply the
respective materials, are coupled to the transport pipe 60. However, after mixing
a melting material and a functional material, the materials may be supplied through
one transport pipe coupled to the transport pipe 60, through which the defibrated
fibers DF are transported. In addition, such a transport pipe may be disposed in the
fibrous-web forming machine 100. In such a case, for example, fixed amounts of melting-resin
fibers and a fire retardant are mixed in the forming drum 101.
[0064] In addition, it is possible to impart incombustibility to the formed defibrated-cotton
sheet (fibrous web) (S) by disposing a liquid atomizer 130 and by adding a water-soluble
fire retardant functioning as a functional material (for example, APINON-145 (produced
by SANWA CHEMICAL CO., LTD.)) to the liquid atomized by the liquid atomizer 130.
[0065] A second shape-maintaining sheet (N
2) is supplied from a second-shape-maintaining-sheet supply roller 82 to a process
after through the fibrous-web forming machine 100 and the liquid atomizer 130. The
second shape-maintaining sheet (N
2) to be supplied from the second-shape-maintaining-sheet supply roller 82 is a cover
of an upper surface (second surface) of the defibrated-cotton sheet (fibrous web)
(S) formed by the fibrous-web forming machine 100.
[0066] Both woven fabric and nonwoven fabric are usable for the second shape-maintaining
sheet (N
2) in the present disclosure. In the embodiment, similarly to the first shape-maintaining
sheet (N
1), ecule (registered trademark) 3151A, which is a polyester filament nonwoven fabric
manufactured through spunbonding by TOYOBO CO., LTD., is used for the second shape-maintaining
sheet (N
2).
[0067] The embodiment employs the following process. The first shape-maintaining sheet (N
1) is supplied from the first-shape-maintaining-sheet supply roller 81 to the fibrous-web
forming machine 100. After the defibrated-cotton sheet (fibrous web) (S) is formed
on the first shape-maintaining sheet (Ni), the second shape-maintaining sheet (N
2) is supplied from the second-shape-maintaining-sheet supply roller 82 and then covers
the upper surface of the defibrated-cotton sheet (fibrous web) (S).
[0068] Alternatively, it is possible to employ the following process. The first-shape-maintaining-sheet
supply roller 81 and the second-shape-maintaining-sheet supply roller 82 are disposed
in a section after through (downstream of) the fibrous-web forming machine 100. The
defibrated-cotton sheet (fibrous web) (S) formed by the fibrous-web forming machine
100 is then held between the first shape-maintaining sheet (N
1) and the second shape-maintaining sheet (N
2).
[0069] Next, the embodiment employs a configuration in which the defibrated-cotton sheet
(fibrous web) (S) reaches a buffer section 140 after the defibrated-cotton sheet (fibrous
web) (S) is formed on the first shape-maintaining sheet (N
1) and before the second shape-maintaining sheet (N
2) is supplied to the second surface of the defibrated-cotton sheet (fibrous web) (S).
[0070] The embodiment may employ a configuration in which the buffer section 140 is disposed
after the second shape-maintaining sheet (N
2) supplied from the second-shape-maintaining-sheet supply roller 82 is disposed on
the second surface of the defibrated-cotton sheet (fibrous web) (S).
[0071] As illustrated in FIG. 2, a fiber structure (M) yet to be subjected to heating and
compression is in the state in which the first shape-maintaining sheet (N
1) is disposed on the first surface of the defibrated-cotton sheet (fibrous web) (S)
and in which the second shape-maintaining sheet (N
2) is disposed on the second surface of the defibrated-cotton sheet (fibrous web) (S).
The thread-like objects in the defibrated-cotton sheet (fibrous web) (S) are the melting-resin
fibers that are a melting material. In FIG. 2, the fire retardant that is a functional
material is omitted and not illustrated in the defibrated-cotton sheet (fibrous web)
(S).
[0072] Next, the defibrated-cotton sheet (fibrous web) (S) illustrated in FIG. 1, whose
second surface is covered, is transported to a heating-and-compression mechanism 150.
The heating-and-compression mechanism 150 holds the defibrated-cotton sheet (fibrous
web) (S), which is a transported object, between a first substrate 151 and a second
substrate 152, which is configured to move up and down, and performs hot pressing
through which the defibrated-cotton sheet (fibrous web) (S) is simultaneously heated
and compressed. The first substrate 151 and the second substrate 152 each include
a heater. The heater can heat the sheet held between the first substrate 151 and the
second substrate 152.
[0073] FIG. 4 is a schematic diagram illustrating heating and compression according to the
embodiment of the present disclosure and a state in which a melting material is melted.
As illustrated in FIG. 4, the defibrated-cotton sheet (fibrous web) (S) is pressed
while the surfaces thereof are heated by the heating-and-compression mechanism 150
(the first substrate 151 and the second substrate 152). Thus, there can be a large
amount of the melting material (high ratio of the melted component) that melts and
exudes to the surfaces of the defibrated-cotton sheet (fibrous web) (S), which are
in contact with the first shape-maintaining sheet (N
1) and the second shape-maintaining sheet (N
2). As a result, the numbers of the fused points (or the fusion areas) between the
defibrated-cotton sheet (fibrous web) (S) and the first shape-maintaining sheet (N
1) and between the defibrated-cotton sheet (fibrous web) (S) and the second shape-maintaining
sheet (N
2) increase. Accordingly, the defibrated-cotton sheet (fibrous web) (S) firmly adheres
to the first shape-maintaining sheet (N
1) and the second shape-maintaining sheet (N
2).
[0074] The defibrated-cotton sheet (fibrous web) (S) is compressed and heated by the heating-and-compression
mechanism 150. As a result, the melting material mixed in the defibrated-cotton sheet
(fibrous web) (S) is heated and fuses tightly with the defibrated fibers DF. This
contributes to maintenance of the strength and the shape of the fiber structure and
to prevention of dispersion of fibers from the fiber structure.
[0075] By melting and hardening the melting material, the first shape-maintaining sheet
(N
1) adheres to the defibrated-cotton sheet (fibrous web) (S) at the first surface of
the defibrated-cotton sheet (fibrous web) (S), and the second shape-maintaining sheet
(N
2) adheres to the defibrated-cotton sheet (fibrous web) (S) at the second surface of
the defibrated-cotton sheet (fibrous web) (S).
[0076] In addition, the strength of the defibrated-cotton sheet (fibrous web) (S) as the
fiber structure can be further increased by removing excess moisture through compression
and heating in the heating-and-compression mechanism 150.
[0077] The heating process and the compression process may be independently performed. However,
it is preferable to simultaneously heat and compress a material. Preferably, the heating
time of a material is the time for which the temperature of the material is increased
to the temperature at which the melting fibers near the cores of the material can
melt. In addition, heating and compression are batch processing, and, to make sufficient
heating time, it is thus preferable to dispose the buffer section 140 in a section
before the heating-and-compression mechanism 150. The buffer section 140 can be realized
by moving up and down a so-called dancer roller (bridge roller). Although the buffer
section 140 is disposed in a section before the second shape-maintaining sheet (N
2) is supplied, it is also possible to employ a configuration in which the buffer section
140 is disposed in a section after the second shape-maintaining sheet (N
2) is supplied and before the heating-and-compression mechanism 150.
[0078] After finishing heating and compression, it is required that the heated and compressed
fiber structure be rapidly moved and then another defibrated-cotton sheet (fibrous
web) (S), which is another material to be heated and compressed, be set. Thus, it
is preferable to dispose a mechanism in which a needle is inserted into the exit of
the heating-and-compression mechanism 150 to hold and extract the heated and compressed
fiber structure. More preferably, the mechanism has a cleaning function because fibers
may adhere to the heating and compressing surfaces. For example, it can be proposed
to employ a method in which a sheet made of polytetrafluoroethylene (PTFE) or other
materials is periodically wound. When the equipment is not in operation, the heating-and-compression
mechanism 150 is in a state of being moved and retracted in a direction intersecting
the transport direction.
[0079] In the embodiment, the heating-and-compression mechanism 150 is composed of the first
substrate 151 and the second substrate 152, which is configured to move up and down.
However, the heating-and-compression mechanism 150 may be composed of heating-and-compression
rollers. Such heating-and-compression rollers are configured to continuously prepare
the fiber structure and thus do not have to be provided with a buffer.
[0080] A sheet of the fiber structure (M) obtained through the recycling process as described
above is cut into a desired size and shape by a cutter 160. The sheets into which
the sheet of the fiber structure (M) is cut are each stacked as a whole fiber structure
on, for example, a stacker 170 and are cooled. For example, an ultrasonic cutter is
preferably used as the cutter 160. The fiber structure may be cut by such an ultrasonic
cutter in a width direction of the fiber structure or in the width direction and the
direction opposite to the width direction, that is, in the reciprocating directions.
For example, a rotary cutter or an octagonal rotary cutter may be used other than
an ultrasonic cutter. A whole fiber structure is then cut with, for example, a Thomson
die and is formed into a desired size and shape to form the reclaimed fiber structure
(M). The reclaimed fiber structure (M) is preferably usable for, for example, sound-absorbing
materials, which absorb sound, cushioning materials (packing materials), which absorb
shocks (external force), and materials for forming dies.
[0081] The strength and the rigidity of the fiber structure (M) in the present disclosure
are maintained by firmly adhering the defibrated-cotton sheet (fibrous web) (S) to
the first shape-maintaining sheet (N
1) and to the second shape-maintaining sheet (N
2). Thus, when the fiber structure (M) is cut or cut out as described above, the first
shape-maintaining sheet (N
1) and the second shape-maintaining sheet (N
2) are unlikely to be peeled, and thus the fiber structure (M) can be cut with high
accuracy. In addition, it is possible to achieve an effect of enabling smooth operations
during, for example, handling.
[0082] The adhesive strengths between the defibrated-cotton sheet (fibrous web) (S) and
the first shape-maintaining sheet (N
1) and between the defibrated-cotton sheet (fibrous web) (S) and the second shape-maintaining
sheet (N
2) were tested to select the proper fiber fineness of a melting-resin fiber as a melting
material. Thus, this is described in detail below.
[0083] FIG. 5 illustrates an outline of a peeling test method. The peeling test was performed
to quantify the adhesive strength between the defibrated-cotton sheet (fibrous web)
(S) and the first shape-maintaining sheet (N
1) (or the second shape-maintaining sheet (N
2)). In FIG. 5, the reclaimed fiber structure (M) used as a sample has a width of about
20 mm and a length of about 120 mm. One end of the reclaimed fiber structure (M) was
held between a base and a holding plate. The first shape-maintaining sheet (N
1) was peeled by about 15 mm from the other end of the reclaimed fiber structure (M),
and the peeled portion of the first shape-maintaining sheet (N
1) was held with a clamp. A weight was suspended from the clamp to measure the minimum
weight under which the first shape-maintaining sheet (N
1) was continuously peeled. The peeling strength (N/m) per unit width was then calculated
by using an expression: minimum weight (kg) × 9.8/width (mm).
[0084] Any sample contains, relative to the weight of the defibrated-cotton sheet (fibrous
web) (S), 20% by weight of the melting-resin fibers as a melting material mixed in
the defibrated-cotton sheet (fibrous web) (S). Tetoron (registered trademark), which
is a polyester fiber for dry nonwoven fabric and is produced by TEIJIN LIMITED, was
used for the melting material. Four kinds of melting-resin fibers having a fiber fineness
of 1.1 dtex, a fiber fineness of 1.7 dtex, a fiber fineness of 2.2 dtex, and a fiber
fineness of 3.3 dtex were used for the test. FIG. 6 illustrates the peeling strength
(N/m) depending on each fiber fineness of the melting-resin fibers.
[0085] As is clear from FIG. 6, the peeling strength (N/m) increases as the fiber fineness
(dtex) of the melting-resin fibers decreases. In other words, it is clear that the
peeling strength (N/m) increases as the fiber fineness of the melting-resin fibers
decreases and thus the adhesive strength between the defibrated-cotton sheet (fibrous
web) (S) and the first shape-maintaining sheet (N
1) increases. The fiber fineness of melting-resin fibers is preferably 2.0 dtex or
less because the peeling strength (N/m) is preferably about 15 N/m or more to reduce
friction and to prevent separation of fibers during handling of the reclaimed fiber
structure (M).
[0086] As described above, the adhesive strength between the defibrated-cotton sheet (fibrous
web) (S) and the first shape-maintaining sheet (N
1) (or the second shape-maintaining sheet (N
2)) increases as the fiber fineness of melting-resin fibers decreases. It is considered
that this is because the number of the melting-resin fibers exposed from both surface
(interfaces B
1 and B
2 in FIGS. 2, 3, and 4) of the defibrated-cotton sheet (fibrous web) (S) increases
due to small fiber fineness of the melting-resin fibers in the defibrated-cotton sheet
(fibrous web) (S), and thus the number of contact points to be adhered to each other
increases.
[0087] In the equipment for manufacturing the fiber structure in the present disclosure
and a method for manufacturing the fiber structure in the present disclosure, the
shape-maintaining sheets (N
1 and N
2) are respectively supplied to the first surface and the second surface opposite to
the first surface of the defibrated-cotton sheet (fibrous web) (S) in which melting-resin
fibers as a melting material are mixed. The defibrated-cotton sheet (fibrous web)
(S) to which the shape-maintaining sheets (N
1 and N
2) are supplied is simultaneously heated and compressed to adhere the shape-maintaining
sheets (N
1 and N
2) to the defibrated-cotton sheet (fibrous web) (S). Thus, the equipment and the method
for manufacturing a fiber structure in the present disclosure enable a fiber structure
to have great ease of handling without, for example, losing the shape and to have
the properties required for the fiber structure in various applications.
[0088] Next, another embodiment of the present disclosure will be described. FIG. 7 is a
schematic diagram illustrating a schematic configuration of equipment for manufacturing
a fiber structure according to another embodiment of the present disclosure. In FIG.
7, components having the same reference signs as those in the above embodiment are
the same components as those in the above embodiment and are not described.
[0089] The embodiment differs from the above embodiment in that, first, the airflow suctioned
by the suction device 110 is led into the inlet 31 of the dry defibrator 30 by using
a transport pipe 180 in the embodiment. Thus, the coarsely crushed pieces moved from
the coarse crusher 10 enter the dry defibrator 30 by being urged by such an airflow.
This configuration enables such an airflow to be used efficiently without being wasted
and the airflow velocity at the outlet 32 of the dry defibrator 30 to be further higher
than that in the above embodiment.
[0090] As described above, in the equipment and the method for manufacturing a fiber structure
in the present disclosure, the reclaimed fiber structure (M) is manufactured by mixing
melting-resin fibers into defibrated fibers. Thus, with the equipment and the method
for manufacturing a fiber structure in the present disclosure, it is possible to manufacture
a fiber structure that has great ease of handling without, for example, losing the
shape and that has the properties required for the fiber structure in various applications.
[0091] In the equipment and the method for manufacturing a fiber structure in the present
disclosure, the first shape-maintaining sheet (N
1) and the second shape-maintaining sheet (N
2) are respectively supplied to the first surface and the second surface opposite to
the first surface of the absorber in which melting-resin fibers are mixed. The defibrated-cotton
sheet (fibrous web) (S) to which the first shape-maintaining sheet (N
1) and the second shape-maintaining sheet (N
2) are supplied is simultaneously heated and compressed to adhere the first shape-maintaining
sheet (N
1) and the second shape-maintaining sheet (N
2) to the defibrated-cotton sheet (fibrous web) (S). Thus, with the equipment and the
method for manufacturing a fiber structure in the present disclosure, it is possible
to manufacture a fiber structure that has great ease of handling without, for example,
losing the shape and that has the properties required for the fiber structure in various
applications.
[0092] According to the equipment and the method for manufacturing a fiber structure in
the present disclosure, the equipment has a configuration in which as little water
as possible is used (water resources are not consumed in large amounts) and thus has
a simple configuration in which the amount of water treatment equipment can be reduced.
In addition, the equipment does not have to include, for example, a large heater for
removing water and thus can achieve high energy efficiency in wastepaper recycling.