U.S. patent application number 10/925391 was filed with the patent office on 2005-01-27 for non-woven fabrics and production method thereof, production apparatus used for the production method, cushion materials, filters, non-woven fabric structures using the same and non-woven fabric suitable to cushion materials.
This patent application is currently assigned to KANEBO, LTD.. Invention is credited to Nagata, Makio, Onoue, Hiroshi, Watanabe, Noboru, Yoshida, Hiroji.
Application Number | 20050020171 10/925391 |
Document ID | / |
Family ID | 34084854 |
Filed Date | 2005-01-27 |
United States Patent
Application |
20050020171 |
Kind Code |
A1 |
Yoshida, Hiroji ; et
al. |
January 27, 2005 |
Non-woven fabrics and production method thereof, production
apparatus used for the production method, cushion materials,
filters, non-woven fabric structures using the same and non-woven
fabric suitable to cushion materials
Abstract
This invention concerns a non-woven fabric obtained by
interweaving fibers, and relates to non-woven fabrics in which the
constituent fibers have three dimensional randomicity in view of
the directionality, a production method and a production apparatus
therefor, and a non-woven fabric suitable to cushion materials,
filters and non-woven fabric structures using the same.
Inventors: |
Yoshida, Hiroji;
(Okazaki-shi, JP) ; Nagata, Makio; (Hofu-shi,
JP) ; Watanabe, Noboru; (Sabae-shi, JP) ;
Onoue, Hiroshi; (Osaka-shi, JP) |
Correspondence
Address: |
HOGAN & HARTSON L.L.P.
500 S. GRAND AVENUE
SUITE 1900
LOS ANGELES
CA
90071-2611
US
|
Assignee: |
KANEBO, LTD.
|
Family ID: |
34084854 |
Appl. No.: |
10/925391 |
Filed: |
August 25, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10925391 |
Aug 25, 2004 |
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09786213 |
May 21, 2001 |
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09786213 |
May 21, 2001 |
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PCT/JP99/04687 |
Aug 30, 1999 |
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Current U.S.
Class: |
442/327 ;
442/361; 442/415 |
Current CPC
Class: |
D04H 1/48 20130101; Y10T
442/60 20150401; D04H 1/732 20130101; D04H 1/5414 20200501; D04H
1/5418 20200501; D04H 1/72 20130101; Y10T 442/637 20150401; D04H
1/5412 20200501; B01D 39/163 20130101; Y10T 442/697 20150401 |
Class at
Publication: |
442/327 ;
442/361; 442/415 |
International
Class: |
D04H 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 1, 1998 |
JP |
10-246888 |
Apr 15, 1999 |
JP |
11-107657 |
Jun 17, 1999 |
JP |
11-170813 |
Jun 17, 1999 |
JP |
11-170814 |
Jul 28, 1999 |
JP |
11-213410 |
Claims
1-9. (Canceled)
10. A non-woven fabric structure produced by preliminarily opening
fibers by a preliminary fiber opening, then accumulating fibers so
as to automatically stack them vertically to a portion of low
accumulation level by using an air stream, then applying primary
heat fusion by a heat fusing treatment to form a non-woven fabric,
forming the non-woven fabric into fiber lumps at least smaller than
the non-woven fabric, forming the fiber lumps into a desired shape
and then applying secondary heat fusion by a heat fusing
treatment.
11-12. (canceled)
13. A non-woven fabric of a three dimensional structure comprising,
at least two types of fibers, which is produced by preliminary
opening short fibers by a preliminary opening machine, and the
fibers discharged from the opener roller being automatically
directed by the air stream from the blower to a portion in the feed
trunk where the level of the raw material is low, wherein the flow
resistance of air is low in said portion, then accumulating short
fibers so as to automatically stack them vertically to a portion of
a low stacking level by using an air stream, and in which one of
constituent fibers contains an ingredient having a melting point
lower than that of other fibers and which is substantially bonded
at portions of contact between each of the fibers and in which the
fibers are arranged along random directions in at least two
surfaces of the three dimensional structure, and which have a
thickness of more than 5 mm.
14. A non-woven fabric as defined claim 13, wherein the constituent
fibers comprise core-sheath type heat fusible fibers and fibers of
1.5 denier or less.
15. A method of producing a non-woven fabric, which comprises
preliminary opening short fibers by a preliminary opening machine,
then the fibers discharged from the opener roller being
automatically directed by the air stream from the blower to a
portion in the feed trunk where the level of the raw material is
low, wherein the flow resistance of air is low in said portion,
then accumulating short fibers so as to automatically stack them
vertically to a portion of a low stacking level by using an air
stream, and in which one of constituent fibers containing an
ingredient having a melting point lower than that of other fibers
and then substantially bonding at portions of contact between each
of the fibers.
Description
TECHNICAL FIELD
[0001] This invention concerns non-woven fabrics obtained by
interweaving short fibers and, more specifically, relates to
non-woven fabrics in which the short fibers constituting the fabric
have a three dimensional randomicity in view of the directionality,
a production method thereof, a production apparatus, cushion
materials, filters and non-woven structures, and non-woven fabrics
suitable to cushion materials.
BACKGROUND ART
[0002] Heretofore, for producing webs used as non-woven fabrics,
they have been produced by arranging fibers in parallel to some
extent while combing fibers by a cylinder and a card clothing using
a carding machine used in a carding step and then scraping off and
collecting fibers transferred to needle heads of a offer by a comb
or the like (carding method). Further, they have been produced by a
method of scattering short fibers in air and then collecting them
into a sheet-like shape on a metal net (air lay method). Further,
as a made of utilizing such non-woven fabrics, they are used for
sound absorbing materials such as for vehicle or residential uses,
or sound shielding walls of highways and it has been known that the
sound absorbing characteristics can be improved as the fiber denier
of constituent fibers is smaller.
[0003] Further, Japanese Patent Laid-Open No. 110370/1998 describes
that more favorable sound absorbing characteristics are generally
exhibited in a case of using fibers for sound absorbing materials
as the sound absorbing materials have higher density and, increased
thickness and the denier of constituent fibers is finer, and
further that when fibers are arranged along random directions
within a surface parallel with the surface of the sound absorbing
material, more excellent sound absorbing property can be provided
compared, for example, with those in which fibers are arranged
along one direction, for example, as those obtained by putting the
fibers to a card into webs and laminating the webs.
[0004] However, even when webs are intended to be produced by using
fibers of fine denier as the constituent fibers by the carding
method, the fibers sink into the card clothing of the carding
machine or form neps to extremely deteriorate the quality or lower
the machine operationability if the denier is less than 1.5 denier.
Further, in the carding machine, since the webs are formed under
carding as described previously, the fiber are always arranged in a
predetermined direction. Further, in the air lay method, it is
difficult to attain a laminate state having a sufficiently uniform
thickness to result in unevenness in the sound absorbing
characteristics of the non-woven fabrics, which is not preferred in
view of the quality.
[0005] Further, the Japanese Patent Laid-Open No. 1103070/1998
describes that non-woven fabrics can be produced in which fibers
are arranged at random in a surface parallel with the surface of
sound absorbing materials, by mixing constituent fibers, then
mixing and opening them by carding and then applying blow molding
by using an air stream. However, since fibers are once arranged in
one direction by a carding treatment in the carding machine before
blowing, fiber orientation in the obtained non-woven fabrics has no
sufficient two dimensional randomicity. Further, since the fibers
are accumulated by the air stream blow molding in a direction
perpendicular to the surface of the sound absorbing materials, it
involves a drawback of easily suffering from peeling in the
laminating direction.
[0006] Further, Japanese Patent Laid-Open No. 209514/1996 discloses
a technique for cushion materials having excellent heat resistance,
durability and cushioning property by meandering a continuous
linear body of thermoplastic resin having an extremely large fiber
denier (300 denier or more) to form three dimensional random loops,
whereby the entire network structure comprising three dimensional
random loops integrated by fusion deforms to absorb stresses when
undergoing large deformation by extremely large stresses, and
restores the structure into the original shape after relieving of
the stresses by the development of rubbery elasticity of the
elastic resin.
[0007] However, even when webs are intended to be produced by using
fibers of 100 denier or more as the constituent fibers by the
carding method, the fibers of the large denier slip off the card
clothing of the carding machine and the fibers can not be scraped
off and collected by a comb or the like, to remarkably deteriorate
the machine operationability. Furthermore, since webs are formed
under carding in the carding machine, the fibers are always
arranged in a predetermined direction. Further, it is difficult to
attain a laminate state having a sufficiently uniform thickness by
the air lay method and unevenness is caused to the characteristics
of the cushion material in the direction of the thickness, which is
not preferred in view of the quality.
[0008] Further, Japanese Patent Laid-Open No. 68061/1995 describes
that a thermoplastic elastic resin is melted by heating to a
temperature higher by 10 to 80.degree. C. than the melting point,
discharged downward from a nozzle having plural orifices and
lowered spontaneously to form loops, in which the loop radius and
the denier of the linear bodies are determined depending on the
distance between the nozzle surface and a take-up conveyer disposed
on a cooling medium for solidifying the resin, the melt viscosity
of the resin, the pore diameter of the orifice and the discharging
amount. That is, no desired three dimensional linear bodies can be
obtained unless such production conditions are determined
specifically, so that they can not be produced easily. Further, no
desired cushion materials can be obtained without using the
thermoplastic elastic resin. Use of the thermoplastic elastic resin
involves a problem that the production cost increases and the
products become heavy for obtaining a desired impact resilience
since the impact resilience per one denier of the fibers used and
the impact resilience per unit density of the non-woven fabric
structure are small.
[0009] Further, as a mode of utilizing the non-woven fabric as a
filter, Japanese Patent Laid-Open No. 209514/1996 discloses a
technique of preparing webs of fine denier and webs of large denier
respectively, combining them into a fiber structure and using the
same as a filter in order to maintain the collecting effect while
restricting the pressure loss by using extremely large fibers.
[0010] However, even when webs are intended to be produced by using
fibers of 1000 denier or more as the constituent fibers by the
carding method, the fibers of the large denier slip off the card
clothing of the carding machine and the fibers can not be scraped
off and collected by a comb or the like to remarkably deteriorate
the machine operationability. Furthermore, since webs are formed
under carding in the carding machine, the fibers are always
arranged in a predetermined direction. Further, it is difficult to
attain a laminate state having a sufficiently uniform thickness by
the air lay method and unevenness is caused to the characteristics
of the filter in the direction of the thickness, which is not
preferred in view of the quality.
[0011] Further, in the technique as described in Japanese Patent
Laid-Open No. 209514/1996, fibers are arranged at random
irrespective of the longitudinal/lateral directions, but those
arranged at random in longitudinal/lateral/height directions can
not be produced. Accordingly, a filter having excellent collecting
characteristics in the three directions can not be produced.
Accordingly, it is not suitable to such a use as sterical filters
intended for collection in multi-directions.
[0012] Further, Japanese Patent Laid-Open No. 94061/1994 discloses
a sheet-like non-woven fabric produced by using fibers such as
polyester as a raw material, and molding the fibers into a fiber
assembly by a charging method of blowing the fibers together with
air into a mold. Further, there is also a method of producing a
non-woven structure having a complicate sterical structure such as
automobile seat cushions, by manufacturing the seat cushion
divisionally for each portion having a simple shape and then
assembling them.
[0013] However, in the blow molding method disclosed in Japanese
Patent Laid-Open No. 294061/1994, it is difficult to make the
density distribution in the seat cushion uniform as the molding
product and, if it is intended to be uniform, the density has to be
increased extremely and, as a result, the produced non-woven fabric
structure is heavy. Further, in the method of patching non-woven
fabrics, the number of small parts is increased in a seat cushion
of a complicate shape, which greatly increases the production
cost.
[0014] Further, since the temperature in a vehicle is elevated up
to 70-100.degree. C. in the summer season under direct sunlight in
a state where doors are closed, it has been demanded for the
automobile seat cushion materials to improve the restorability
after applying a load for a long time in a high temperature
atmosphere. Further, since the mattress materials for use in beds
are subjected to a laundry treatment or sterilizing treatment at a
high temperature in their stacked state, it has been demanded that
they cause no deformation by expansion or compression after
applying the load in a high temperature atmosphere.
[0015] Further, it has been known that when products used for
cushion materials such as vehicle seat materials or mattresses for
home or hospital uses are applied with a smoothing oil agent such
as silicon on the surface of the constituent fibers thereof, the
restorability after long time compression in a normal temperature
or high temperature atmosphere can be improved. For example,
Japanese Patent Laid-Open No. 137350/1997 describes a cushion
structure in which a smoothing oil agent is coated on a fiber
surface to reduce friction between each of the fibers and improve
the restorability upon removing the load.
[0016] However, even when it is intended to produce webs by using
fibers coated with the smoothing oil agent as the constituent
fibers in the carding method, fibers coated with the smoothing oil
agent slip off the card clothing of a carding machine and the
fibers can not be scraped off and collected by a comb or the line,
to remarkably deteriorate the machine operationability. Further,
when it is coated to the surface after being formed into the
cushion structure, the smoothing oil agent is not coated to the
surfaces of the individual constituent fibers failing to develop
the desired effect. Further, in the carding machine, since the webs
are formed under carding, fibers are always arranged in a
predetermined direct ion. Further, in the air lay method, it is
difficult to attain a lamination state having a sufficiently
uniform thickness and unevenness is caused to the cushioning
characteristic of the non-woven fabric, which is not preferred in
view of the quality.
[0017] Then, with an aim of improving the sound absorbing
characteristics, improving the cushioning property and improving
the collecting effect, this invention intends to provide non-woven
fabrics having fiber orientation which is uniform and three
dimensionally at random, a production method capable of producing
such non-woven fabrics simply and easily, a production apparatus
used for the production method, cushion materials, filters and
non-woven fabric structures using the same, as well as non-woven
fabrics suitable to the cushion materials.
DISCLOSURE OF THE INVENTION
[0018] This invention provides a non-woven fabric of a three
dimensional structure comprising fibers, which is bonded
substantially at portions of contact between each of the fibers and
the fibers are arranged along random directions in at least two
surfaces of the three dimensional structure.
[0019] Further, this invention provides a non-woven fabric of a
three dimensional structure comprising at least two types of fibers
in which one of constituent fibers contains an ingredient having a
melting point lower than that of other fibers, which is
substantially bonded at portions of contact between each of the
fibers and in which the fibers are arranged along random directions
in at least two surfaces of the three dimensional structure.
[0020] Further, this invention provides a non-woven fabric in which
constituent fibers comprise core-sheath type thermo-fusible fibers
and fibers of 1.5 denier or less.
[0021] Further, this invention provides a non-woven fabric produced
by preliminarily opening fibers by a preliminary opening machine,
then accumulating fibers so as to automatically stack them
vertically to a portion of a low stacking level by using an air
stream and then substantially bonding portions of contact between
each of the fibers.
[0022] Further, this invention provides a method of producing a
non-woven fabric, which comprises preliminarily opening fibers by a
preliminary opening machine, then accumulating fibers so as to
automatically stack them vertically to a portion of a low stacking
level by using an air stream and then substantially bonding
portions of contact between each of the fibers.
[0023] Further, this invention provides an apparatus for producing
a non-woven fabric comprising a mechanism of preliminarily opening
fibers by a preliminary opening machine, a mechanism of stacking
fibers so as to automatically stack them vertically to a portion of
a low stacking level by using an air stream and then substantially
bonding portions of contact between each of fibers.
[0024] Further, this invention provides a cushion material using a
three dimensional structure of a non-woven fabric constituted with
fibers which are substantially bonded at portions of contact
between each of the fibers of the three dimensional structure and
in which the fibers constituting the three dimensional structure
contain fibers with a fiber denier of 100 denier or more, and the
fibers are arranged along random directions in at least two
surfaces of the three dimensional structure.
[0025] Further, this invention provides a filter using a three
dimensional structure of a non-woven fabric constituted with fibers
which is substantially bonded at portions of contact between each
of the fibers of the three dimensional structure and in which the
fibers constituting the three dimensional structure contain fibers
with a fiber denier of 1000 denier or more, and the fibers are
arranged along random directions in at least two surfaces of the
three dimensional structure.
[0026] Further, this invention provides a non-woven fabric
structure constituted by bonding plural fiber lumps each comprising
fibers in which the fiber lumps comprise at least two kinds of
fibers, one of constituent fibers contains an ingredient having a
melting point lower than that of other fibers, the fiber lumps are
substantially bonded at portions of contact between each of the
fibers with the low melting ingredient and the fibers constituting
the fiber lump are arranged along random directions in at least two
surfaces of the fiber lump.
[0027] Further, this invention provides a non-woven fabric
structure produced by preliminarily opening fibers by a preliminary
fiber opening, then accumulating fibers so as to automatically
stack them vertically to a portion of low accumulation level by
using an air stream, then applying primary heat fusion by a heat
fusing treatment to form a non-woven fabric, forming the non-woven
fabric into fiber lumps at least smaller than the non-woven fabric,
forming the fiber lumps into a desired shape and then applying
secondary heat fusion by a heat fusing treatment.
[0028] This invention provides a non-woven fabric of a three
dimensional structure comprising fibers, which is bonded
substantially at portions of contact between each of the fibers and
in which the three dimensional structure contains fibers coated
with a silicon oil agent and the fibers are arranged along random
directions in at least two surfaces of the three dimensional
structure.
[0029] Further, this invention provides a non-woven fabric of a
three dimensional structure comprising at least two kinds of
fibers, in which one of the constituent fibers contains an
ingredient having a lower melting point than that of other fibers,
at least one of the fibers other than the fibers containing the low
melting ingredient is coated with a silicon oil agent, they are
substantially bonded at portions of contact between each of the
fibers with the low melting ingredient, and the fibers are arranged
along random directions at least in two surfaces of the three
dimensional structural.
BRIEF EXPLANATION OF DRAWINGS
[0030] FIG. 1 is a schematic view illustrating a state of a
non-woven fabric structure according to this invention,
[0031] FIG. 2 is an electron microscopic photograph of a non-woven
fabric structure according to this invention applied with a super
heating treatment,
[0032] FIG. 3 is a side elevational view of a production apparatus
according to this invention and
[0033] FIG. 4 is a front elevational view of the production
apparatus according to this invention.
BEST MODE FOR PRACTICING THE INVENTION
[0034] The non-woven fabric according to this invention is to be
described below. This example is merely an example of embodiments
and the invention is not restricted to such example.
[0035] The non-woven fabric according to this invention mainly
comprises polyester fibers substantially bonded at portions of
contact between each of the fibers and in which constituent fibers
are arranged along random directions in at least two surfaces of
the non-woven fabric structure.
[0036] The fibers constituting the non-woven fabric include, for
example, polyester fibers having a side-by-side structure and
having self-crimping developability (fiber denier: 6.0 denier,
fiber length: 51 mm), extremely fine polyester fibers referred to
as fine denier (fiber denier: 0.5 denier, fiber length: 51 mm), and
core-sheath type composite polyester fibers in which the melting
point of fibers constituting the sheath is set lowest among the
fibers constituting the non-woven fabric according to this
invention (fiber denier: 2.0 denier, fiber length: 38 mm). When the
fibers are restricted to the polyester type, they are advantageous
in view of re-melting upon recycle use.
[0037] The produced non-woven fabric according to this invention
has a thin substantially rectangular outer profile. The most
prominent feature of the non-woven fabric according to this
invention is that orientation of the fibers in at least two
surfaces of the rectangle is at random. This is produced in the
production apparatus to be described later and the production
method using the production apparatus, and randomicity for the
orientation of the fibers in at least two surfaces (hereinafter
referred to as "three dimensional randomicity") will be described
specifically.
[0038] The three dimensional randomicity means that the
directionality (orientation) of the individual fibers constituting
the non-woven fabric is not aligned in a predetermined direction.
For quantitatively determining the randomicity, the three
dimensional randomicity is defined by the procedures as described
below.
[0039] At first, samples for at least two surfaces of a cuboidal
non-woven fabric (about 2 cm.times.2 cm) are set to a stereoscopic
microscope and image data at a magnification ratio of about 40 are
taken into a image processing apparatus (Image Analyzer V10,
manufactured by Toyo Boseki Co.). Then, the image data for the
original image are put to "Binarization Processing" by a TOKS
method and bisected such that the portion for the fibers is a black
region and the portion for the background is a white region.
Further, "Finely sectioning processing" is applied to the
background (white region) to make the size uniform. The direction
of the background is numericalized by "Fillet radius ratio (y/x
ratio)" and the average value thereof (average value for about 10
data) is defined as a quantified three dimensional randomicity as
an index showing the directionality of fibers of the non-woven
fabric per se.
[0040] The Fillet radius is a kind of calculation processing
commands for images in the image processing apparatus to conduct
the following calculational processing. Assuming the abscissa as X
axis and the ordinate as Y axis in the image processing apparatus,
the background (white region) in the image data is calculationally
processed for each of the fibers constituting the non-woven fabric
applied with "Finely sectioning processing" and made uniform for
the with, by defining the length of a projected horizontal radius
on the horizontal X-axis as Fillet radius X, and defining the
length of a projected vertical radius on the vertical Y-axis as the
Fillet radius y. The calculational processing is conducted on every
fibers and, based on the Fillet radius ratio as the result of the
calculation, Fillet radius ratio (y/x ratio) is determined on every
fibers. The thus calculationally processed Fillet radius ratio is
1.00 when the directionality is completely at random. It is 1.00 or
less as the directionality approaches the X-axis while 1.00 or more
as it approaches the Y-axis. When the Fillet radius ratio is
determined for every fibers and the average value is determined,
randomicity is attained when the Fillet radius ratio approaches
1.00. When the processing is conducted to at least two surfaces of
the cuboidal non-woven fabric, and both of the Fillet radius ratio
in the respective surfaces are near 1.00, it can be said to have
the three dimensional randomicity.
[0041] Table 2 and Table 3 show the Fillet radius ratio as the
result of operation for the non-woven fabric according to this
invention (example) and for the non-woven fabric produced by the
carding method as the comparative example (for the production
condition such as denier and the fiber length of each non-woven
fabric, refer to Table 1)
1 TABLE 1 Usual Self-crimping Basis finess developable Binder unit
Thickness Fine fiber fiber fiber g/m.sup.2 mm Denier 0.5 d 2.0 d
6.0 d 2.0 d Fiber length 38 mm 51 mm 51 mm 51 mm Example 65% 15%
20% 700 40 Comp. Example 65% 15% 20% 1200 40
[0042]
2 TABLE 2 Comparative Example Example Surface 1 0.98 0.93 Surface 2
0.98 0.93 Surface 3 0.97 0.91 Average 0.98 0.92
[0043]
3 TABLE 3 Comparative Example Example Lateral side 1 1.01 0.94
Lateral side 2 0.97 0.95 Lateral side 3 0.98 0.94 Average 0.99
0.94
[0044] As apparent from Table 2 and Table 3, there is a difference
in that the Fillet radius ratio of the non-woven fabric according
to this invention is near 1.00, whereas that of the non-woven
fabric produced by the carding method is less than 1.00.
Accordingly, when the fiber orientation in at least two surfaces of
the non-woven fabric structure is within a range from 0.95 to 1.05,
this can be defined as having a three dimensional randomicity.
[0045] Then, the result of evaluation for the performance of the
non-woven fabric according to this invention is shown. The
performance was evaluated in accordance with the sound absorption
ratio (at 1000 Hz, 2000 Hz) and static spring constant at 5 kgf as
the sound absorbing characteristics in a case of using the
non-woven fabric as the sound absorbing material. Table 4 shows the
result.
4 TABLE 4 Comparative Example Example Thickness (mm) 35.4 34.5
Basis unit (g/m.sup.2) 728 1187 Density (g/cm.sup.3) 0.021 0.034
25% compression hardness 2.4 4.5 (kgf/314 cm.sup.2) 65% compression
hardness 10.2 27.0 (kgf/314 cm.sup.2) Sound absorption ratio at
80.3 85.5 1000 Hz (%) Sound absorption ratio at 99.8 99.7 2000 Hz
(%) Static spring constant at 0.44 0.68 5 kgf (kgf/mm)
[0046] Sound absorption characteristics and the mechanical
characteristics shown in Table 4 were measured as below. The sound
absorption ratio is a vertical incident sound absorption ratio
according to JIS-A1405, which was measured by a 2-microphone method
by using a Multi-Channel Analyzing System model 3550, manufactured
by Bruel & Kjar Co. (software: BZ5087 model 2-channel analyzing
software). The measured sound area is from 0 to 5000 Hz, N=8.
Further, the static spring constant at 5 kgf was measured by an
automatic hardness tester according to JASO-M304. When a load of
0.5 kgf is applied by a pressure plate of 200 mm.phi. to the upper
surface of a sample sized 300.times.300 mm and 50 mm thickness as a
measuring specimen, the thickness is defined as the initial
thickness. This is compressed to 0-65% at a pressing rate of 50
mm/min and the static spring constant at 5 kgf is measured. As the
static spring constant is lower, the sound vibration performance in
the low frequency region (500-1000 Hz) is more favorable.
[0047] As apparent from Table 4, there is a distinct difference for
the sound absorbing characteristic between the non-woven fabric
produced by the existent carding method and the non-woven fabric
according to this invention. The first reason of developing the
difference is that fine that could not be put to the carding
machine and could not be used as the constituent fibers for the
non-woven fabric in the existent non-woven fabric increased the
total surface area of the fibers per unit volume of the non-woven
fabric. That is, the sound absorption is taken place when sound
waves (waves of air molecules) enter the non-woven fabric, and are
brought into contact with the surface of the fibers to convert the
sound energy into the frictional heat energy. Therefore, for the
non-woven fabrics of an identical basis weight, the number of
constituent fibers per unit volume increases as the average denier
is lowered to increase the total surface area and conversion of the
sound waves into the heat energy is increased to improve the sound
absorbing characteristic. Fine of about 0.5 denier that could not
be put to the carding machine so far develop such an effect.
[0048] The second reason is that the effect is developed by the
three dimensional randomicity not attained in the existent
non-woven fabrics. It is considered that since random reflection of
propagating sound waves in the non-woven fabric was increased by
the provision of the three dimensional randomicity, multiple
reflection of sounds proceeds more tending to cause friction
between fibers, so that the sound absorbing characteristic was
improved. Those having so-called two dimensional randomicity
produced by blow molding after subjecting to the carding machine as
described in Japanese Patent Laid-Open No. 110370/1998 have
orientation along the advancing direction of the fibers in the
carding machine due to the characteristics of the carding machine,
so that no improvement for the sound absorbing characteristic can
be expected as in this invention.
[0049] Further, when considering with the macro point of view, the
absorbing material has three dimensional degree of freedom as a
whole in the case of the three dimensional randomicity. This is
considered that while those of the two dimensional randomicity have
a characteristic that sounds incident along the lamination
direction do not propagate between the layers (this means that when
the incident direction of the sounds and the direction of the
lamination are in parallel with each other, the sound passes
through and the sound absorbing characteristic is not favorable),
whereas those of the three dimensional randomicity also have the
characteristic capable of obtaining desired sound absorbing
characteristic irrespective of the incident direction. That is, it
is considered that since the direction of the reaction of force by
the sound propagation is not uniform as the entire fiber assembly,
the sound absorbing characteristic is improved more than that in
the case of the two-dimensional randomicity.
[0050] Then, the cushion material according to this invention is to
be described. This example merely illustrates an example of
embodiments and the invention is not restricted only to this
example.
[0051] The cushion material according to this invention uses a
non-woven fabric that mainly comprises polyester fibers partially
containing fibers of 100 denier or more which is substantially
bonded at portions of contacts between each of the fibers and in
which the constituent fibers are arranged along random directions
in at least two surfaces of the three dimensional structure.
[0052] The fibers constituting the non-woven fabric used for the
cushion material include, for example, polyester fibers having a
side-by-side structure and having self-crimping developability,
polyester fibers of core-sheath type composite fibers, fine of 100
denier or more and core-sheath type composite polyester fibers with
the melting point of fibers constituting the sheath being set
lowest among the fibers constituting the non-woven fabric according
to this invention. When the fibers are restricted to the polyester
type, they are advantageous in remelting upon recyclic use.
[0053] Among the constituent fibers used in this invention, fine
are preferably of 100 denier or more and 5000 denier or less.
Fibers of less than 100 denier are soft and difficult to maintain
the shape of the cushion material and fibers of 5000 denier or more
can not provide favorable cushioning property since individual
constituent fibers are excessively hard.
[0054] Further, the fine are preferably contained by at least 30%
by weight or more and, more preferably, 50% by weight or more. If
the mixing ratio is lower, the function and effect of the fine can
not be developed undesirably. On the other hand, if the mixing
ratio of the fine is higher, since production of the fiber webs by
the carding is extremely difficult due to the lowering of the
machine operationability, they are produced by the production
method to be described later.
[0055] The cushioning material produced according to this invention
has a thin substantially cuboidal outer shape. The feature of the
cushion material according to this invention rises in that the
orientation of the fibers at least in the two surfaces of the
cuboidal body is at random.
[0056] For the cushion material according to this invention
(example) and the cushion material produced by the carding method
as a comparative example (comparative example), the Fillet radius
ratio as a result of calculation is shown in Table 6 and Table 7
(refer to Table 5 for the conditions such as denier of each cushion
material)
5 TABLE 5 Usual Self-crimping Basis finess developable Binder unit
Thickness fine fiber fiber fiber g/m.sup.2 mm Denier 500 d 2.0 d
13.0 d 2.0 d Fiber length 38 mm 51 mm 51 mm 51 mm Example 65% 15%
20% 1200 40 Comp. Example 15% 65% 20% 1200 40
[0057]
6 TABLE 6 Comparative Example Example Surface 1 1.01 0.94 Surface 2
0.99 0.95 Surface 3 1.02 0.93 Average 1.01 0.94
[0058]
7 TABLE 7 Comparative Example Example Lateral side 1 0.99 0.93
Lateral side 2 1.01 0.95 Lateral side 3 1.01 0.92 Average 1.00
0.93
[0059] As apparent Table 6 and Table 7, there is a difference in
that the Fillet radius ratio of the cushion material according to
this invention is near 1.00, whereas that of the cushion material
proceed by the carding method is less than 1.00. Accordingly, the
fiber orientability at least in the two surfaces of the cushion
material within the range from 0.95 to 1.05 can be defined as
having the three dimensional randomicity.
[0060] The performance was evaluated in accordance with the
compressive hardness and the strain ratio as the cushioning
characteristic of the cushion material. The result is shown in
Table 8.
8 TABLE 8 Comparative Example Example Thickness (mm) 40.8 40.2
Basis unit (g/m.sup.2) 1190 1187 Density (g/cm.sup.3) 0.0291 0.0295
Compression good bad hardness Strain ratio ordinary bad
[0061] For the compression hardness, among the cushioning
characteristics shown in Table 8, samples are cut out each into 30
cm.times.30 cm size and compressed to 65% of the initial thickness
by a disk of 200 mm diameter at a constant speed of 50 mm/min and
then removed with the load by using an automatic hardness tester
manufactured by Kobunshi Keiki Corporation "ASKERAF200" and an S/S
curve is measured. In the evaluation, the hardness at 25%
compression is indicated as "good" for 10 kgf or more and less than
20 kgf, as "ordinary" for 20 kgf or more and less than 30 kgf, and
as "bad" for less than 10 kgf or more than 30 kgf. If it is 10 kgf
or more and less than 20 kgf, appropriate cushioning property can
be obtained in a case of use as the cushion material for sheet such
as of automobiles. Further, since the excessive compression
deformation due to load fluctuation can be suppressed and the
bottomed feeling can be decreased for the cushioning material, it
is particularly preferred.
[0062] Further, for the strain ratio, a sample is cut out into 10
cm.times.10 cm size and the initial thickness is measured.
Subsequently, the sample is put between iron plates and compressed
to 50% of the initial thickness. The sample is left as it is at
22.degree. C., 65% RH for 15 hours. After leaving 15 hours, the
load is removed and the compressed thickness is measured and the
strain ratio is calculated by the following equation.
Strain ratio (%)=(Initial thickness-Thickness after
compression).times.100/Initial thickness
[0063] The evaluation for the strain ratio was indicated as "good"
for less than 5%, as "ordinary" for 5% or more and less than 15%
and "bad" for 15% or more.
[0064] As apparent from Table 8, the cushion material of the
example can be used for a long period of time, that is, the
buckling resistance is improved.
[0065] It is considered that the first reason of developing the
difference is that fine that could not be used in a great amount in
the cushion material using the non-woven fabric produced by the
existent method, whereas the fine contained at least by more than
30% by weight or more of the constituent fibers develop such as
effect in this invention. That is, it is considered that fine,
difficult to be put to the carding machine if mixed in a great
amount so far, can develop such an effect.
[0066] Further, as the second reason, it is considered that such
characteristic is developed by the three-dimensional random
structure produced without using the carding method and by the
mixing of a great amount of fine. That is, it is considered that
incorporation of the fine in a great amount can appropriately
maintain the inter-fiber gaps developing the impact resilience as
the cushion material, to prevent buckling due to aging and,
further, three dimensional random arrangement of fibers provides
the three dimensional oriented constitution as the entire cushion
material and such three dimensional constitution can provide
uniform impact resilience in all of the directions to give
excellent cushioning property.
[0067] Then, the filter according to this invention is to be
explained. This example merely shows an example of embodiments and
this invention is not restricted to such example.
[0068] The filter according to this invention mainly comprises
polyester type fibers containing fibers of 1000 denier or more in a
portion thereof which is substantially bonded at portions of
contact between each of the fibers and in which the constituent
fibers are oriented along random directions in at least two
surfaces of the three dimensional structure.
[0069] The fibers constituting the non-woven fabric used for the
filter include, for example, polyester fibers having a side-by-side
structure and having self-crimping developability, fine of 1000
denier or more and core-sheath type composite polyester fibers with
the melting point of fibers constituting the sheath being set
lowest among the fibers constituting the non-woven fabric according
to this invention. When the fibers are restricted to the polyester
type, they are advantageous in remelting upon recyclic use.
[0070] Among the constituent fibers used in this invention, the
fine are preferably of 1000 denier or more and 3000 denier or less.
If they are less than 1000 denier, gaps between constituent fibers
are small tending to increase the pressure loss and cause clogging
when used as the filter, and it is difficult to maintain the shape
of the filter. On the other hand, if they exceed 3000 denier, the
fibers are excessively hard to increase the gaps formed between the
fibers larger, failing to collect dusts sufficiently.
[0071] Further, the fine are preferably contained by at least 30%
by weight or more and, more preferably, 50% by weight or more.
Lower mixing ratio is not desirable since the function and effect
of the fine can not be developed. On the other hand, if the mixing
ratio of the fine is greater, since production of the fiber webs by
the carding is extremely difficult due to the lowering of the
machine operationability, they are produced by the production
method to be described later.
[0072] The filter produced according to this invention has a thin
cuboidal outer shape. The feature of the filter according to this
invention resides in that the orientation of the fibers at least in
the two surfaces of the cuboidal body is at random.
[0073] For the filter according to this invention (example) and the
filter produced by the carding method as a comparative example
(comparative example), the Fillet radius ratio as a result of
calculation is shown in Table 10 and Table 11 (For the conditions
such as the denier of each filter, refer to Table 9).
9 TABLE 9 Usual Self-crimping Basis finess developable Binder unit
Thickness Fine fiber fiber fiber g/m.sup.2 mm Denier 1000 d 2.0 d
6.0 d 2.0 d Fiber length 64 mm 51 mm 51 mm 51 mm Example 65% 15%
20% 700 20 Comp. Example 65% 15% 20% 700 20
[0074]
10 TABLE 10 Comparative Example Example Surface 1 0.97 0.93 Surface
2 0.96 0.93 Surface 3 0.99 0.91 Average 0.97 0.92
[0075]
11 TABLE 11 Comparative Example Example Lateral side 1 1.02 0.94
Lateral side 2 1.01 0.95 Lateral side 3 0.99 0.94 Average 1.01
0.94
[0076] As apparent from Table 10 and Table 11, there is a
difference in that the Fillet radius ratio of the filter according
to this invention is near 1.00, whereas that of the filter proceed
by the carding method is less than 1.00. Accordingly, the fiber
orientation at least in the two surfaces of the filter within the
range from 0.95 to 1.05 can be defined as having the three
dimensional randomicity.
[0077] Then, the result of evaluation for the performance of the
filter according to this invention is shown. The performance was
evaluated in accordance with the dust absorbing characteristic as
one of the indexes in a case of using the filter. The initial
pressure loss of the example was 0.10 mmAq, while the initial
pressure loss of the comparative example was 0.20 mmAq.
[0078] (Measuring Method for Dust Absorbing Characteristic)
[0079] Using the filters of the example and the comparative
example, the dust absorbing amount till the final pressure loss of
the filter reached 10 mmAq was measured under the identical
conditions at a test area of 0.372 m.sup.2 (face area), a dust
density of 70 mg/m.sup.3 (dust concentration) and a face velocity
of 1.0 m/sec (face velocity). The result is shown in Table 12.
12 TABLE 12 Comparative Example Example Thickness (mm) 20.5 19.8
Basis unit (g/m.sup.2) 728 705 Density (g/cm.sup.3) 0.0355 0.0356
Initial pressure loss 0.10 0.20 (mmAq) Average collection 75 73
efficiency (%) Dust absorbing ratio 2000 1000 (g/cm.sup.2)
[0080] As apparent from Table 12, the average collection efficiency
is 75% for the example and 73% for the comparative example, and the
dust absorbing amount is 2000 g/m.sup.2 for the example and 1000
g/m.sup.2 for the comparative example and it is apparent that the
filter of the example can be used over a long period of time.
[0081] It is supposed as the first reason for developing the
difference that the fine contained at least by 30% by weight or
more of the constituent fibers can properly maintain the gaps
between constituent fibers without extremely increasing the
pressure loss, while such fine could not be used in a great amount
for the filter using the non-woven fabric produced by the existent
method. That is, the fine, which were difficult to be put to the
carding machine if mixed in a great amount, can develop such an
effect.
[0082] It is considered as the second reason that such
characteristic is developed by the three dimensional random
structure and mixing of a great amount of the fine. That is, it is
considered that by mixing a great amount of the fine, the filter
can properly maintain the inter-fiber gaps as the dust collecting
region of the filter to prevent great increase of pressure loss
and, further, it has the three dimensional random arrangement of
the fibers as the filter material by the three dimensional fiber
orientation and has excellent dust collecting efficiency by such
three dimensional constitution. That is, it is considered that
since the paths of dusts upon passing through the filter are not
uniform as the entire three dimensional structure of the filter,
the dust absorbing characteristic can be improved more than that in
the case of the two dimensional randomicity.
[0083] Then, the non-woven fabric structure according to this
invention is to be described. This example is merely an example of
embodiments and the invention is not restricted only to such
example.
[0084] The fiber lump constituting the non-woven fabric structure
according to this invention is to be explained. The fiber lump is
produced by pulverizing the special non-woven fabric described
previously.
[0085] It is also possible to apply a heat treatment to the special
non-woven fabric before pulverization as described above. The heat
treatment is referred to as the primary heat fusing treatment and
distinguished from the secondary heat fusing treatment as the heat
fusing treatment of applying a heat fusing treatment to the fiber
lump to form a non-woven fabric structure. The primary heat fusing
treatment is applied at a temperature lower than the melting point
of the fibers other than the low melting fibers and higher than the
temperature of developing the fusibility of the low melting fibers.
Such primary heat fusing treatment bonds other constituent fibers
that intersect with the low melting fibers in the inside of the
fiber lump at the intersections to provide the fiber lump with
shape stability, as well as the low melting fibers provide the
fiber lump with an appropriate rigidity in cooperation with the
supporting function of other constituent fibers.
[0086] The special non-woven fabric produced in the step described
above is pulverized by using a square pelletizer or rotary type
universal pulverizer to obtain fiber lumps of a desired size.
However, pulverization of the non-woven fabric is not restricted to
that applied by the pulverizer described above. Further, the rotary
type universal pulverizer has good productivity but somewhat
injures the fibers, whereas those pulverized by using the square
pelletizer suffer from no injuries for the fibers and have good
impact resilience.
[0087] As the characteristic of the fiber lump, the shape with a
smaller difference between the major axis and the minor axis is
preferred and a shape with a minor axis of 2 to 100 mm and, more
preferably, 5 to 20 mm is desirable. The shape with a greater
difference between the major axis and the minor axis is not
preferred since the moldability is poor. The impact resilience upon
25% compression is preferably from 0.1 to 30.times.10.sup.-2
kgf/cm.sup.2 and, more preferably, 1.0 to 10.times.10.sup.-2
kgf/cm.sup.2.
[0088] The non-woven fabric structure according to this invention
has a structure formed by making the fiber lump into a desired
shape and then applying a secondary heat fusing treatment thereby
heat fusing the fiber lumps to each other. As the shape, the main
portion, except for special portions such as ends or attaching
portions upon use, preferably has an average thickness of 5 mm or
more. When the average thickness is 5 mm or more, sufficient
rigidity as the support can be maintained and fixed feeling, stable
feeling and cushioning property are obtained favorably.
[0089] Further, the average density of the non-woven fabric is
preferably from 0.01 to 0.50 g/cm.sup.3. The range described above
is preferred since sufficient strains can be obtained as the
support and the feeling upon touch is preferred and an appropriate
cushioning property can be obtained favorably.
[0090] The form based on the second heat fusing treatment between
each of the fiber lumps forming the non-woven fabric structure is
to be explained. The fiber lumps are in intimate contact with each
other in a state formed into a desired shape by the secondary heat
fusing treatment and the fiber lumps are bonded to each other by
the hot melting of the low melting fibers as the constituent
fibers.
[0091] Accordingly, in a case of applying the primary heat fusing
treatment before forming the fiber lump, the non-woven fabric
structure according to this invention has a feature in that it has
a fused state based on the primary heat fusing treatment and the
fused state based on the secondary heat fusing treatment in the
inside. The primary heat fused form has a characteristic that the
volume of primary heat fusing portion > volume of secondary heat
fusing portion for the melting applied of the low melting fibers
also incorporated with the secondary heat fusing treatment and,
further, the primary heat fusing form has a node-like form. The
secondary heat fused form has a feature of bonding between the
fiber lumps to each other. It is considered that remarkable
improvement of the cushioning property is developed by such a
form.
[0092] Then, the result for the evaluation of the performance of
the non-woven fabric structure according to this invention is
shown. The performance was evaluated in accordance with the
residual strain ratio as a recovery rate, in a case of using the
non-woven fabric as the cushion material, when a load is applied
for a predetermined time to the upper surface of the sample under a
predetermined condition as the recovery characteristic to the
compressive load and then the load is removed. The result is shown
in Table 13.
[0093] The method of measuring the restorability under a normal
temperature atmosphere and the evaluation method are as explained
for the cushion material.
[0094] For the measuring method of the restorability in a high
temperature atmosphere, and the evaluation method, a sample is cut
out into 10 cm.times.10 cm size and the initial thickness is
measured. Then, the sample is put between iron plates and
compressed to 50% of the initial thickness. It was left as it is at
70.degree. C. for 15 hours in a drier. After 15 hours, the load is
removed and the thickness after compression is measured and the
strain ratio is calculated according to the following equation.
Strain ratio (%)=(Initial thickness-thickness after
compression)/Initial thickness.times.100
[0095] The evaluation for the strain ratio is indicated as "good"
for less than 25%, as "ordinary" for 25% or more and less than 35%
and as "bad" for 35% or more.
[0096] The measuring method and the evaluation method for the
cushioning property are as explained for the cushion material.
13 TABLE 13 Strain ratio Strain ratio at normal at high Cushioning
temperature temperature property Moldability This good good good
very good invention Convenient good ordinary ordinary bad card
lamina-tion method
[0097] As apparent from Table 13, there is a remarkable difference
for the compression strain ratio between the non-woven fabric
structure produced by the existent carding method and the non-woven
fabric structure according to this invention. The reason for
developing the difference resides in that the fiber lumps
constitute the non-woven fabric structure and the fiber lumps are
bonded to each other at desired points of contact, and that the
fiber lumps have a predetermined compression strength.
[0098] FIG. 1 shows a schematic view of a non-woven fabric
structure according to this invention. As shown in FIG. 1, the
non-woven fabric structure according to this invention has a
composite structure having a supporting function due to the low
melting fibers in the inside of the fiber lump and a supporting
function due to the bonding between each of the fiber lumps.
[0099] That is, with a micro point of view, when a load is applied
at a high temperature, since the low melting fibers in the inside
of the fiber lump provides the fiber lump itself with an
appropriate rigidity in cooperation with the supporting function of
other fibers, they undergo a load in the inside of the fiber lumps.
With a macro point of view, impact resilience between each of the
fiber lumps is developed due to the state where the fiber lumps in
the inside of the structure are arranged at random to each other,
and the impact resilience, the stress dispersibility, the
elasticity restorability and the compressive durability are
improved by reduction of the inner stress due to the impact
resilience.
[0100] Further, since the fiber lump itself has a desired impact
resilience coefficient, even when the fiber lumps are blown molded,
it can avoid the difficulty that the fiber lumps are crushed to
each other making it difficult to control the desired density.
Further, since the fiber lump has appropriate points of bonding,
the fiber lump themselves have many points of bondings, so that
shape stability as the non-woven fabric structure is improved.
[0101] Particularly, the non-woven fabric structure obtained by
using highly crystalline core-sheath type low melting fibers of
large denier and by applying primary and secondary heat fusing
treatments with wet heat have favorable evaluation. In addition to
the reason described above, as apparent from the electron
microscopic photograph shown in FIG. 2, a portion larger than the
low melting fibers before heat fusing treatment is formed as a node
between one and other intersections of the low melting fiber and
the low melting fiber or between the low melting fiber and other
constituent fiber.
[0102] The node maybe formed by merely elevating the temperature
but, in this case, the temperature is raised considerably than the
melting point of the highly crystalline low melting fibers (for
example, by 30 to 50.degree. C.), which results in a drawback of
tending to cause thermal degradation to polyester fibers as the
main fibers of other fibers, as well as regular polyester for the
core of the core-sheath type low melting fibers due to high
temperature. Accordingly, the node can be formed more effectively
by using the low melting fibers as described above and by applying
a wet heat treatment at 160.degree. C. for 10 min.
[0103] As a result, when taking notice on one low melting fiber, it
has a cross-like melting point as a point of bonding at the
intersection, and has a portion comprising a core and a shape in
which the sheath flows by over melting and forms a ball on the
sheath to the core (hereinafter referred to as a node-like
structure).
[0104] In the non-woven fabric structure according to this
invention in a case of having a node-like structure in the inside
as described above, the constituent fibers that intersect with the
low melting fibers are bonded at the intersections to provide the
non-woven fabric structure with the shape stability. The low
melting fibers, in cooperation with the supporting function of
other constituent fibers, provide the non-woven fabric structure
with an appropriate rigidity. Further, against the load under
severe conditions, not only the thermal fusion points at the
intersections but also the composite structure comprising the
node-like structure formed of the sheath welded to the core and
core portions before and after the same can develop remarkable
shape restorability.
[0105] That is, even when a compression load is applied in an
atmosphere lower than the glass transition point of the low melting
polymer, it is considered that since the structure has no evenly
uniform radius but has a node portion enlarged intermittently after
the removal of the load, it has a rigidity different from the
structure of the uniform radius. On the other hand, it is
considered that node-like structure provides not only the rigidity
but also a function like that a spring structure.
[0106] Further, since fibers constituting the fiber lump has the
random structure in at least two surfaces in view of
directionality, the compressive strain ratio is remarkable
different between the non-woven fabric structure produced by the
existent carding method and the non-woven fabric structure
according to this invention as apparent from Table 13. It is
considered for the reason of developing the difference that the
fiber lumps constitutes the non-woven fabric structure and that the
constituent fibers in the inside of the fiber lumps have a three
dimensional random arrangement structure in view of the
directionality. That is, when a load is applied at a high
temperature, with a macro point of view, the low melting fibers in
the inside of the fiber lump provide the fiber lump itself with
appropriate rigidity in corporation with the supporting function of
other constituent fibers, so that the portion receives the load.
With a macro point of view, it is considered that the arrangement
of the fiber lumps to each other in the three dimensional random
arrangement in the structure develops the impact resilience between
each of the fiber lumps and lowering of the inner stress due to the
impact resilience improves the impact resiliency, stress
dispersibility, elasticity restorability and durability. Further,
it is considered that the entire cushion material has a three
dimensional degree of freedom by the three dimensional random fiber
arrangement and such three dimensional degree of freedom can
provide excellent shape storability after removal of the load. That
is, it is considered that since the directions of the reaction of
the force exerted from the load is not uniform for the entire
assembly of the non-woven fabric structure, the restoration
characteristic is improved more than that in the case of the two
dimensional random.
[0107] Then, the non-woven fabric suitable to the cushion material
according to this invention is to be explained. This example is
merely an example of embodiments and the invention is not
restricted only to such example.
[0108] The non-woven fabric suitable to the cushion material
according to this invention mainly comprises polyester type fibers
containing smooth fibers coated with a silicon type oil agent to a
portion thereof, which is anon-woven fabric suitable to the cushion
material which is substantially bonded at portions of contact
between each of the fibers and in which the constituent fibers are
arranged along random directions at least within two surfaces of
the non-woven fabric structure.
[0109] The fibers constituting the non-woven fabric are, for
example, polyester fibers having a side-by-side structure and
having self-crimping developability, smooth fibers coated with a
silicon type oil agent and, core-sheath type polyester composite
fibers, with the melting point of fibers constituting the sheath
being set lowest among the fibers constituting the non-woven fabric
according to this invention. When the fibers are restricted to the
polyester type, they are advantageous in view of remelting upon
recyclic use.
[0110] Among the constituent fibers used in this invention, the
surface of the smooth fibers is coated with the silicon type oil
agent, and the smoothing oil agent used concretely is an oil agent
for fibers capable of providing fibers with smoothness, usually,
silicon-containing oil, particularly, silicon type oil agent,
silicon modified oil and fluoro modified oil being recommended.
Specifically, they include, non-reactive silicon oils such as
dimethyl polysiloxane and diphenyl polysiloxane. In addition,
methyl hydrogen polysiloxane and epoxy group-containing
polysiloxane may also be used and they preferably used by applying
heat treatment after the depositing treatment.
[0111] In a case where the silicon type oil agent is not coated,
since the friction on the fiber surface increases and interweaving
between the fibers to each other used in the non-woven fabric
increases, impact resilience of the high crimping fibers is
worsened. Therefore, restorability upon removing load after long
time compression is worsened inappropriately. Further, the silicon
type oil agent may be coated to the highly crimping fibers. In this
case, the friction is further lowered preferably. However, it is
not appropriate to coat the surface of the low melting fibers since
bonding by the heat fusion is inhibited, thereby making the molding
fabrication difficult.
[0112] Further, the silicon oil agent-coated fibers are preferably
incorporated by at least 40% by weight or more and, more
preferably, 50% by weight or more. Below the mixing ratio described
above, no satisfactory restorability is obtained upon removing the
load after long time compression. On the other hand, in excess of
the mixing ratio described above, since the production of the fiber
webs by the carding is extremely difficult by the lowering of the
machine operability, they are produced by the production method as
described specifically below.
[0113] The produced non-woven fabric suitable to the cushion
material according to this invention has a thin cuboidal outer
shape. The feature of non-woven fabric suitable to the cushion
material according to this invention resides in that the
orientation at least in the two surfaces of the cuboidal body is at
random.
[0114] Table 15 and Table 16 show the Fillet radius ratio as the
result of calculation for the non-woven fabric suitable to the
cushion material according to this invention (Example 1) and for
the non-woven fabric produced by the carding method as the
comparative example (Comparative Example 4) suitable to the cushion
material (for the production condition such as the denier of each
cushion material, refer to Table 14).
14 TABLE 14 Physical property of non-woven fabric Composition for
the non-woven fabric structure (wt %) structure Other constituent
fibers (matrix fiber) Low melting fiber Thickness Density High
crimping fiber Smooth fiber (binder fiber) (mm) (g/cm.sup.3) Number
of polymer 2 1 1 1 2 ingredient Melting point High 270 270 270 core
(.degree. C.) shrinkage 270 270 Low sheath shrinkage 160 270 Oil
agent usual usual silicon usual usual Denier 6 6 3 3 2 Fiber length
(mm) 51 51 51 51 51 Example 1 30 60 10 50 0.025 Example 2 30 60 10
50 0.025 Comp. Example 1 60 30 10 50 0.025 Comp. Example 2 60 30 10
50 0.025 Comp. Example 3 60 30 10 50 0.025 Comp. Example 4 30 60 10
50 0.025
[0115]
15 TABLE 15 Comparative Example 1 Example 4 Surface 1 0.98 0.94
Surface 2 1.00 0.94 Surface 3 0.99 0.92 Average 0.99 0.93
[0116]
16 TABLE 16 Comparative Example 1 Example 4 Lateral side 1 0.99
0.95 Lateral side 2 0.98 0.95 Lateral side 3 0.98 0.93 Average 0.98
0.94
[0117] As apparent from Table 15 and Table 16, there is a
difference in that the Fillet radius ratio of the non-woven fabric
suitable to the cushion material according to this invention is
near 1.00, whereas that of the cushion material produced by the
carding method is less than 1.00. Accordingly, when the fiber
orientation in at least two surfaces of the cushion material is
within a range from 0.95 to 1.05, this can be defined as having a
three dimensional randomicity.
[0118] The performance was evaluated in accordance with the
restorability in a normal temperature atmosphere, the restorability
in a high temperature atmosphere and the cushioning property in a
case of using the non-woven fabric suitable to the cushion material
as the cushion material.
[0119] The measuring method in the normal temperature atmosphere
and the evaluation method for the restorability are as explained
for the cushion material. The measuring method for the
restorability in the high temperature atmosphere and the evaluation
method are as explained for the non-woven fabric structure.
[0120] For the measuring method and the evaluation method of the
cushioning property, a sample is cut out into 30 cm.times.30 cm
size, and compressed to 65% of the initial thickness by a disk of
200 mm diameter at a constant speed of 50 mm/min, and the load is
measured. The evaluation is indicated for 65% compression as "very
good" for 20 kgf or more and less than 30 kgf, as "good" for 17 kgf
or more and 20 kgf or less or 30 kgf or more and less than 33 kgf
and as "bad" for less than 17 kgf or 33 kgf or more. If the
hardness is 20 kgf or more and less than 30 kgf, an appropriate
cushioning property can be obtained when used for the sheet
cushioning material such as of automobiles. Further, it is
particularly preferred since excess compressive deformation of the
cushion material due to fluctuation of load can be suppressed and
the bottomed feeling is also decreased.
17 TABLE 17 Restorability in normal Restorability in high
temperature atmosphere temperature atmosphere Cushioning property
Strain ratio Strain ratio Compression (%) Evaluation (%) Evaluation
hardness (kgf) Evaluation Example 1 4.0 very good 18.6 very good
27.5 very good Example 2 4.5 very good 19.1 very good 27.5 very
good Comp. Example 1 4.8 very good 26.3 ordinary 32.8 good Comp.
Example 2 4.9 very good 27.1 ordinary 30.5 good Comp. Example 3 7.0
good 30.5 bad 45.0 bad Comp. Example 4 11.4 good 32.7 bad 35.0
bad
[0121] As apparent from Table 17, there is a significant different
between Example 1 and Example 2 and other comparative examples
since other constituent fibers applied with silicon are contained
by 60% by weight in the examples. The first reason for developing
the difference is that since smooth fibers applied with silicon,
which could not be used in a great amount so far as the constituent
fibers of the non-woven fabric because of the difficulty of being
put to the carding machine, reduce the friction on the surface of
the non-woven fabric and decrease the entanglement between the
fibers other used in the non-woven fabric, impact resilience of the
highly crimping fibers is enhanced. That is, it is considered that
silicon-coated smooth fibers, which were difficult to be put to the
carding machine when mixed by a great amount, develop such an
effect.
[0122] Further, as the second reason, such characteristic is
developed in combination of the three dimensional random structure
produced not using the carding method and mixing of a great amount
of silicon-coated smooth fibers. It is considered that since the
smoothing oil agent is coated to the fibers, when the non-woven
fabric as the cushion material undergoes compressive deformation,
the impact resilience, the stress dispersibility, the elasticity
restorability and the durability are increased by the improvement
of the slidability between the fibers to each other and lowering of
the inner stress, as well as the cushion material has a three
dimensional degree of freedom as a whole by the three dimensionally
random fiber arrangement, and such three dimensional degree of
freedom provides excellent cushioning property. That is, it is
considered that the cushioning property is improved more than that
in the case of the secondary random structure since the direction
of the reaction of force undergoing from the load is not uniform as
the entire fiber assembly.
[0123] Further, when comparing the examples and Comparative Example
1, it is considered that highly crimping other constituent fibers
develop the function and the effect of improving the cushioning
property in Comparative Example 1 but the function and the effect
of the silicon-applied fibers described above are more remarkable
from the comparison with Example 2.
[0124] (Production Apparatus for Non-Woven Fabric)
[0125] FIG. 3 and FIG. 4 show an example of a non-woven fabric and
a production apparatus for non-woven fabric suitable to cushion
material according to this invention. The cushion material and the
filter are produced by producing the non-woven fabric as shown
below and then cutting the same into a predetermined size.
[0126] The non-woven fabric production apparatus comprises, as
shown in the drawing, a charging duct (1) for charging previously
opened fibers, an exhaust duct (2) for discharging air, an air
outlet 1 (3) in a reserve trunk (4), the reserve trunk (4) for
temporarily storing fibers, a feed roller (5) for feeding fibers
from the reserve trunk (4) to an opener roller (6), and the opener
roller (6) for opening fibers and feeding them to a feed trunk, the
feed trunk (7) for feeding the fibers each of a predetermined
amount to a delivery roller (9), an air outlets 2 (8) in the feed
trunk (7), a delivery roller (9) for delivering a web (W) from the
apparatus, a blower for blowing air to each of the portions of the
apparatus, and a transportation conveyor (10) for transporting the
web (W) to a subsequent step. Air flow is indicated by a blank
arrow and a fiber flow is indicated by a solid arrow.
[0127] The non-woven fabric production apparatus are to be
explained specifically for each of mechanisms.
[0128] <Charging Duct>
[0129] The charging duct (1) is a hollow cuboidal body situated
above the apparatus and having an opening on the side or in the
upper portion. This is a portion to which fibers (tufts)
preliminary opened by an air stream are conveyed and discharged
into the apparatus.
[0130] <Exhaust Dust>
[0131] The exhaust duct (2) is a duct situated near the charging
duct and having an opening in the upper portion, which is adapted
to discharge the air stream used for the transportation of the
fibers (tufts) upon charging into the apparatus to the outside of
the apparatus.
[0132] <Air Outlet 1>
[0133] The air outlet 1 (3) is, for example, a perforated metal
plate formed by opening plural small holes to a flat plate, or
rectangular punched plate and has a structure that the area of the
opening portions is adjustable. Further, as a countermeasure for
suspended fibers, a filter is disposed before discharge out of the
apparatus.
[0134] <Reserve Trunk>
[0135] The reserve trunk (4) has a vertical cylindrical shape for
storing preliminary opened fibers (tufts) in which a feed roller
(5) is disposed to the lower portion thereof. The fibers (tufts)
are once stored in the reserve trunk (4) and then sent by the feed
roller (5) to the opener roller (6).
[0136] <Feed Roller>
[0137] The feed roller (5) is disposed at the bottom of the reserve
tank (4). The feed roller (5) has a teethed wire wound therearound
and is designed such that the diameter is large and the length is
longer by about 50 to 100 mm than the width of the web (W). With
such a constitution, even raw materials such as bulky materials and
those of large fiber length can be reliably delivered.
[0138] Further, the feed roller (5) is connected with an electric
motor capable of variable speed control, for example, an
inverter-controlled AC motor by way of a speed reducer. The speed
control is applied based on the weight date for the web (W) from a
weight checker for detecting the weight of the web (W) disposed to
the exit of the apparatus or the height date for the web (W) from a
sensor for detecting the height of the web (W) disposed at the exit
of the apparatus by feedback control such that the weight and the
thickness of the web (W) are always at predetermined values.
Further, it is also preferred that the weight or the thickness of
the web (W) are always at predetermined values by feedback control
so as to always make the pressure in the feed trunk (7) constant
based on the pressure data measured by the pressure sensor disposed
in the feed trunk (7).
[0139] <Opener Roller>
[0140] The opener roller (6) is disposed below and near the feed
roller (5). The opener roller (6) has several rows of spikes at the
surface and the length is designed so as to be longer by about 50
to 100 mm than the width of the web (W). Further, the opener roller
(6) is connected with an electric motor rotating at a constant
speed by way of a speed reducer. The fibers (tufts) are effectively
opened and supplied to the feed trunk (7) by the interaction
between the opener roller (6) rotating at the constant speed and
the feed roller (5) rotating at a variable speed.
[0141] <Feed Trunk>
[0142] The feed trunk (7) is a hollow cuboidal body having the
opener roller (6) in the upper portion and the delivery roller (9)
in the lower portion and having the air outlet 2 (8) in the
intermediate portion. Fibers (tufts) supplied from the opener
roller (6) are accumulated so as to be uniform in the lateral
direction by the production method to be shown later in the feed
trunk (7) and formed into a web (W).
[0143] <Air Outlet 2>
[0144] The air outlet 2 (8) comprises a perforated metal plate
having plural holes each of small diameter formed in a flat plate
or an apertured plate of a rectangular shape, for example, having a
structure capable of controlling the area for the opening portions,
which is disposed below walls before and after the feed trunk (7)
and disposed over the entire lateral direction of the
apparatus.
[0145] <Delivery Roller>
[0146] The delivery roller (9) comprises, for example, two rollers
opposed in the horizontal direction and designed such that the
length is longer by about 50 to 100 mm than the width of the web
(W). Further, the delivery roller (9) is connected with an electric
motor rotating at a constant speed by way of a speed reducer. The
web (W) accumulated in the feed trunk (7) is discharged out of the
apparatus by the opposing to delivery rollers (9).
[0147] <Transportation Conveyor>
[0148] The transportation conveyor (10) is, for example, a known
belt conveyor for discharging the web (W) produced on the upper
surface thereof to the outside of the apparatus in the horizontal
direction.
[0149] (Production Method of Non-Woven Fabric)
[0150] The non-woven fabric according to this invention is produced
by vertically accumulating preliminary opened fibers using an air
stream, with the direction after extrusion being horizontal. In a
case of mixing binder fibers, it is also preferred to apply a heat
treatment by a heat setter (hot blow treatment, infrared ray
treatment, wet heat treatment or the like), thereby heat forming
the non-woven fabric. In a case of not applying heat fusion, it is
preferred to substantially bond them at portions of contacts
between each of the fibers by mechanical means such as needle
punching.
[0151] The production method of the non-woven fabric is to be
described specifically in the order of steps.
[0152] <Preliminary Fiber Opening Step>
[0153] Fibers (tufts) taken out of raw stocks by a bale opener are
made gradually fine and uniform by an opener generally used, for
example, in mixing and picking steps. A beater, cylinder, spike
roller and teethed roller are disposed to the opener and fiber
compositions are fully opened by the roller mechanism. For
producing a uniform web (W), it is necessary that the fibers
(tufts) are sufficiently opened and the opening rate is preferably
95% or more.
[0154] <Air Transportation Step>
[0155] Opened fibers (tuft) are pneumatically transported from the
opener to the charging duct (1) of the production apparatus
according to this invention.
[0156] <Reserve Step>
[0157] Fibers (tufts) charged from the charging duct (1) of the
apparatus are once stored in the reserve trunk (4). In the reserve
trunk (4), the flow rate of air into the reserve trunk (4) is
adjusted to control the air flow rate such that the filling height
and the filling density in the reserve trunk (4) are constant. That
is, when the pressure in the trunk duct increases by the increase
of the level of the fibers (tufts) or the density thereof in the
reserve trunk (4), the pressure change is detected and the flow
rate of an air stream from the blower is decreased to decrease the
feed amount. On the other hand, when the pressure in the trunk duct
lowers in accordance with the decrease of the level or the density
of the fibers (tufts), the pressure change is detected and the flow
rate of the air stream is increased to increase the stock feed
amount. With such control, the machine operation is not interrupted
and the charging level can be kept constant. The amount of blow is
controlled by the control of the number of rotation of the blower
disposed in the central portion of the apparatus and by changing
the opening area of the air outlet (3).
[0158] <Feed Step>
[0159] Then, the fibers (tufts) are fed into the feed trunk (7). In
this case, the feed roller (5) is disposed at the bottom of the
reserve trunk (4) and the web (W) is supplied by way of the feed
roller (5) to the opener roller (6). As described above, since the
feed roller (5) has the teethed wire wound therearound and the
diameter is set larger, raw materials even of bulky raw materials
and raw materials of longer fiber length can be fed reliably.
[0160] The speed of the feed roller (5) is controlled by detecting
the pressure in the feed trunk (7). Further, since the opener
roller (6) has a constant speed and has several rows of spikes
along the circumference, the fibers (tufts) are further made
uniform and fed to the feed trunk (7). The web (W) in the feed
trunk (7) is uniformly compressed in the direction of the width of
the web (W) in the feed trunk (7) by an air stream generated from
the blower in the apparatus, and the air stream is controlled so as
to return by way of the air outlet 2 (8) to the blower. This can
make the density of the web (W) and the depth of the web (W)
accumulated in the feed trunk (7) constant.
[0161] Since the amount of the web (W) in the feed trunk (7) is
extremely small, the lower portion thereof is not compressed by its
own weight. The web (W) is compressed by the air stream from the
blower and the speed of the feed roller (5) is controlled such that
the compression pressure is constant. That is, the speed is
lowered, that is, the feed amount of the fibers (tufts) is
decreased along with increase of the inner pressure of the feed
trunk (7), whereas the speed of the feed roller (5) is increased,
that is, the feed amount of the fibers (tufts) is increased along
with the lowering of the inner pressure.
[0162] The fibers (tufts) discharged from the opener roller (6) are
automatically directed by the air stream from the blower to a
portion in the feed trunk (7) where the level of the raw material
is low, that is, to a portion where the flow resistance of air is
low. This can eliminate the difference of the level in the raw
material over the entire width of the apparatus in the feed trunk
(7) and, finally, high uniformity can be obtained over the entire
web (W).
[0163] Further, instead of controlling the thickness of the web (W)
by the change of the air stream caused by localization in the
lateral direction as described above, a raw material of an
optionally set weight may be accumulated in accordance with the
actually weighted value of the arriving raw material by an
automatic weighing system such as a load cell system. Further, a
raw material of optionally set weight may be accumulated with the
fibers (tufts) being beaten by a beater instead of the air
stream.
[0164] <Discharge Step>
[0165] The fibers (tufts) in the feed trunk (7) are sent by the
delivery roller (9) out of the apparatus. The discharged web (W) is
transported by the transportation conveyor (10) to a subsequent
step.
[0166] <Subsequent Step 1>
[0167] At first in a case of a web (W) containing heat fusible
fibers, it is subjected to a heat setter. The heat setter is a
known device and has a structure, for example, of allowing the web
(W) to pass through the device having a heat source byway of a
conveyor. The heat source can include, for example, a hot blow
obtained from a combustion gas, high temperature steam and
far-infrared rays. The heat setting temperature is such a
temperature at which the low melting ingredient is melted and the
high melting ingredient is not melted. By the treatment in the
subsequent step 1, the low melting ingredient is melted and
substantially fused at points of contact with the high melting
ingredient.
[0168] <Subsequent Step 2>
[0169] Further, in a case of a web (W) containing the heat fusible
fibers, it is subjected to a wet heat setter in addition to the
treating method described above or in place of the above-mentioned
method. The wet heat setter is a known device and has a structure
of charging the web (W) in a steam vessel and then the steam vessel
is tightly sealed to reduce the pressure and wet heat steams at
high pressure and high temperature are entered. The heat setting
temperature is such a temperature at which the low melting
ingredient is melted and the high melting ingredient is not melted.
By the heat treatment in the subsequent step 2, heat can be
transferred as far as the inside of the web (W) in which the low
melting ingredient is melted throughout the web (W) and fused
substantially at the points of contact with the high melting
ingredient. In such a method, when the web (W) transported on the
transportation conveyor 10 is treated by stacking several of such
webs (W), steams can permeate as far as the inside of them to
enable uniform heat setting. Further, when such several sheets of
webs (W) are stacked, a non-woven fabric of different densities in
the direction of the thickness can be produced easily by stacking
those of different fiber densities. Any of the cases is suitable to
the production of cushion materials.
[0170] <Subsequent Step 3>
[0171] A web (W) whether it includes heat fusion or not can
substantially be bonded at portions of contact between each of the
fibers mechanically in the subsequent step. For example, fibers in
the web (W) are entangled to each other by sticking plural needles
into and out of the web (W) in the vertical direction repeatedly
for a number of times to bond the fibers in the contact portions
thereof.
[0172] Then, a method of producing the non-woven fabric structure
using fiber lumps is to be described.
[0173] The subsequent steps 1 and 2 described above are primary
heat fusing treatment in a case applied to the non-woven fabric
structure using the fiber lumps.
[0174] <Production of Non-Woven Fabric 1>
[0175] A non-woven fabric 1 with 20 mm thickness and 500 g/m.sup.2
of basis weight was obtained by mixing 80% by weight of hollow
conjugate polyester fibers of 6 denier and 51 mm as other
constituent fibers and 20% by weight of low melting polyester
fibers of 2 denier and 51 mm with a melting point of 110.degree. C.
as the low melting fibers, to form a non-woven fabric in the
non-woven fabric production step described above and slightly
entangling them by needle punching.
[0176] <Production of Non-Woven Fabric 2>
[0177] A non-woven fabric 2 with 30 mm thickness and 500 g/M.sup.2
of basis weight was obtained by mixing 80% by weight of hollow
conjugate polyester fibers of 6 denier and 51 mm as other
constituent fibers and 20% by weight of low melting polyester
fibers of 2 denier and 51 mm using a copolyester having a melting
point of 110.degree. C. for a sheath as the low melting fibers, to
form a non-woven fabric in the non-woven fabric production steps
described above and then applying an infrared heat fusing treatment
as the primary heat fusing treatment. The conditions for the
primary heat fusing treatment are at the temperature of an upper
heater of 250.degree. C. and a lower heater of 350.degree. C.
[0178] <Production of Non-woven Fabric 3>
[0179] A non-woven fabric 3 of 30 mm thickness and 500 g/m.sup.2 of
basis weight was obtained by mixing 50% by weight of hollow
conjugate polyester fibers of 6 denier and 51 mm as other
constituent fibers, 30% by weight of silicon oil coated cotton of 6
denier and 51 mm and 20% by weight of core-sheath type low melting
fibers using a copolyester having a melting point of 110.degree. C.
for a sheath, of 2 denier, 51 mm as the low melting fibers, to form
a non-woven fabric in the non-woven fabric production steps
described above and then applying an infrared heat fusing treatment
as the primary heat fusing treatment. The conditions for the
primary heat fusing treatment are at the temperature of an upper
heater of 250.degree. C. and a lower heater of 350.degree. C.
[0180] <Production of Non-Woven Fabric 4>
[0181] A non-woven fabric 4 of 20 mm thickness and 500 g/m.sup.2 of
basis weight was obtained by mixing 80% by weight of hollow
conjugate polyester fibers of 6 denier and 51 mm as other
constituent fibers, and 20% by weight of core-sheath type low
melting fibers using a highly crystalline polyester having a
melting point of 160.degree. C. for a sheath of 15 denier and 51 mm
as the low melting fibers, to form a non-woven fabric in the
non-woven fabric production steps described above and then slightly
entangling them by needle punching.
[0182] <Production of Non-Woven Fabric 5>
[0183] The non-woven fabric 5 with 30 mm thickness and 500
g/m.sup.2 of basis weight was obtained by mixing 80% by weight of
hollow conjugate polyester fibers of 6 denier and 51 mm as other
constituent fibers and 20% by weight of core-sheath type low
melting fibers of 15 denier and 51 mm using a highly crystalline
polyester having a melting point of 160.degree. C. for a sheath as
the low melting fibers, to form a non-woven fabric in the non-woven
fabric production steps described above, and then applying an
infrared heat fusing treatment as the primary heat fusing
treatment. The conditions for the primary heat fusing treatment are
at the temperature of an upper heater of 350.degree. C. and a lower
heater of 450.degree. C.
[0184] <Production of Fiber Lump>
[0185] The non-woven fabrics 1 and 4 produced in the steps
described above were pulverized by using a square pelletizer to
obtain fiber lumps each sized 8000 mm.sup.3 and having an impact
resilience stress at 25% compression of 5.times.10.sup.-2
kgf/cm.sup.2. Further, the non-woven fabrics 2, 3 and 5 applied
with the primary heat fusing treatment were pulverized by a rotary
type universal pulverizer manufactured by Sanriki Seisakusho to
obtain fiber lumps each sized 1000 mm.sup.3 and having impact
resilience stress at 25% compression of 10.times.10.sup.-2
kgf/cm.sup.2. In the pulverization of the non-woven fabric, use of
the pulverizer described above is not limitative. Further, while
the rotary type universal pulverizer shows good productivity but it
somewhat damages the fibers, whereas those pulverized by using the
square pelletizer suffers from no damages to the fibers and show
good impact resilience.
[0186] <Non-Woven Fabric Structure A>
[0187] A mold (molding die) conforming a desired shape is
manufactured, and fiber lumps prepared as described above are mixed
and blown into a molding cavity of the mold. When the fiber lumps
are charged into the mold, only the air for transportation is
released through an exhaust port out of the mold and the fiber
lumps are efficiently charged in the mold.
[0188] Then, after charging the fiber lumps, a secondary heat
fusing treatment is applied. The heat fusing treatment is applied
by blowing a hot blow formed by a hot blow generator by way of a
blowing tube and a duct through a blowing duct into the mold. At
the same time, a pressing machine is operated to shape the charged
fiber lumps into a predetermined configuration and size under
compression.
[0189] Further, instead of the hot blow drying, blowing of super
heated steams into the mold is preferred since there is no
unevenness in the distribution of the temperature and uniform heat
fusing treatment can be attained. In this case, the condition for
the secondary fusing treatment temperature for the non-woven fabric
1 is 130.degree. C., the condition for the secondary fusing
treatment temperature for the non-woven fabric 4 is 190.degree. C.,
the condition for the secondary fusing treatment temperature for
the non-woven fabrics 2 and 3 are 110.degree. C. and the condition
for the secondary fusing treatment temperature for the non-woven
fabric 5 is 160.degree. C. at wet heating. The non-woven fabric
structures produced from the fiber lumps using the non-woven
fabrics 1, 2, 3, 4 and 5 as the raw material are, respectively,
non-woven fabric structures A1, A2, A3, A4 and A5.
[0190] <Non-Woven Fabric Structure B>
[0191] The fiber lumps prepared as described above were measured
batchwise and the secondary heat fusing treatment is applied for
desired amount of weight. In this case, the secondary heat fusing
treatment for the non-woven fabric 1 is used. In this case, the
condition for the secondary heat fusing treatment of the non-woven
fabric 1 is 130.degree. C. and the condition for the secondary heat
fusing treatment of the non-woven fabric 4 is 190.degree. C., the
condition for the secondary heat fusing treatment of the non-woven
fabrics 2 and 3 is 110.degree. C. and the condition for the
secondary heat fusing treatment of the non-woven fabric 5 is
160.degree. C. by wet heating. The non-woven fabric structures
produced from fiber lumps using the non-woven fabrics 1, 2, 3, 4
and 5 as the raw material are, respectively, non-woven fabric
structures B1, B2, B3, B4 and B5.
INDUSTRIAL APPLICABILITY
[0192] The invention according to claim 1 of this invention can
provide a sound absorbing material of good sound absorbing
characteristic suitable to vehicle application use or the like.
[0193] Further, the invention according to claim 2 of this
invention can provide a non-woven fabric of easy handling by
melting of the ingredient having a melting point lower than that of
other fibers.
[0194] Further, the invention according to claim 3 of this
invention can provide a sound absorbing material of good sound
absorbing characteristic, in which the fibers of 1.5 denier or less
can improve the sound absorbing characteristic and which is
suitable to vehicle application use or the like.
[0195] Further, the invention defined in claim 4 can provide a
non-woven fabric not requiring a carding machine and can provide a
non-woven fabric produced at a reduced production cost due to
saving of steps.
[0196] Further, the invention defined in claim 5 has an effect
capable of saving steps since the carding step is not required and
capable of reducing the production cost compared with the existent
production method by the carding method.
[0197] Further, the invention as defined in claim 6 can provide a
non-woven fabric production apparatus capable of saving steps and
reducing the production cost.
[0198] Further, the invention as defined in claim 7 can provide a
cushion material of preferred cushioning property improved with
heat stability and durability.
[0199] Further, the invention as defined in claim 8 can provide a
filter having satisfactory dust collecting characteristic with less
clogging and suitable for use in air or water treatment.
[0200] Further, the invention as defined in claim 9 can provide a
non-woven fabric structure having a structural feature that fiber
lumps of indefinite shape are bonded by heat melting of the
constituent fibers, provided with rigidity between the fiber blocks
to each other and the cushioning property in addition to the
rigidity and the cushioning property of the fiber lumps themselves,
and suitable to automobile application use or application use for
bed mattress.
[0201] Further, the invention as defined in claim 10 can provide at
a reduced cost a non-woven fabric structure suitable to vehicle
application use or application use for bed mattress.
[0202] Further, the invention as defined in claim 11 can provide a
non-woven fabric of preferred cushioning property suitable to
automobile application use.
[0203] Further, the invention as defined in claim 12 can provide a
non-woven fabric suitable to cushion materials easy to handle with
by melting the ingredient having lower melting point than that of
other fibers.
* * * * *