U.S. patent application number 10/472664 was filed with the patent office on 2004-04-29 for high moisture absorbing nonwoven fiber structure and production method therefor.
Invention is credited to Araki, Tadashi, Momoi, Naomichi, Watanabe, Noboru.
Application Number | 20040082246 10/472664 |
Document ID | / |
Family ID | 18938123 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040082246 |
Kind Code |
A1 |
Watanabe, Noboru ; et
al. |
April 29, 2004 |
High moisture absorbing nonwoven fiber structure and production
method therefor
Abstract
A high moisture absorbent nonwoven fabric structure comprising a
moisture absorbing layer mainly consisting of high moisture
absorbent fibers, and surface sheets sandwiching the moisture
absorbing layer to constitute a three-layer structure. The high
moisture absorbent fibers gel on the surfaces thereof by absorbing
water and/or moisture to develop a self-bonding force. The high
moisture absorbent nonwoven fabric has an absorptivity, after five
hours at 20.degree. C. and relative humidity of 65%, of at least 20
wt. %, at least one of the surface sheets has breathability, and
the self-bonding force of high moisture absorbent fibers ensures
bonding between fibers in the moisture absorbing layer and between
the moisture absorbing layer and the surface sheets. The high
moisture absorbent nonwoven fabric structure, which is high in
hygroscopicity, applicable to a small space, and easily recyclable
by heat treating nonwoven fabrics after moisture absorbed, can be
used in a variety of fields such as desiccants and dehumidifying
agents.
Inventors: |
Watanabe, Noboru; (Fukui,
JP) ; Araki, Tadashi; (Yamaguchi, JP) ; Momoi,
Naomichi; (Hyogo, JP) |
Correspondence
Address: |
Kirschstein Ottinger
Israel & SchiffMiller
489 Fifth Avenue
New York
NY
10017-6105
US
|
Family ID: |
18938123 |
Appl. No.: |
10/472664 |
Filed: |
September 19, 2003 |
PCT Filed: |
March 20, 2002 |
PCT NO: |
PCT/JP02/02724 |
Current U.S.
Class: |
442/327 |
Current CPC
Class: |
B32B 5/26 20130101; Y10T
442/60 20150401 |
Class at
Publication: |
442/327 |
International
Class: |
D04H 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 22, 2001 |
JP |
2001-82135 |
Claims
1. A high moisture absorbent nonwoven fabric structure consisting
of a three layers structure comprising a moisture-absorbing layer
consisting mainly of high moisture absorbent fibers and surface
sheets with the moisture-absorbing layer between, characterized in
the following (a).about.(f): (a) that surface of said high moisture
absorbent fiber gels by absorbing water and/or moisture to express
self-adhering activity, (b) that the fibers in the
moisture-absorbing layer adhere each other and the
moisture-absorbing layer and the surface sheets adhere each other
by the self-adhering activity of the high moisture absorbent fiber,
(c) that at least one of the surface sheets has air permeability,
(d) that the thickness of said high moisture absorbent nonwoven
fabric structure is not more than 1.5 mm, (e) that the water
content of said high moisture absorbent nonwoven fabric structure
is 20 to 45 weight %, and (f) that the moisture-absorbing rate of
said high moisture absorbent nonwoven fabric structure is at least
20 weight % under absolute dry condition at 20.degree. C. and 65%
RH after 5 hours.
2. The high moisture absorbent nonwoven fabric structure according
to claim 1, wherein said moisture-absorbing layer consists of high
moisture absorbent fiber alone.
3. The high moisture absorbent nonwoven fabric structure according
to claim 1 or 2, wherein said high moisture absorbent fiber is a
high moisture absorbent fiber of a crosslinked sodium acrylate
type.
4. The high moisture absorbent nonwoven fabric structure according
to any of claims 1 to 3, wherein the apparent density is 0.05 to
0.8 g/cm.sup.3.
5. The high moisture absorbent nonwoven fabric structure according
to any of claims 1 to 4, wherein the high moisture absorbent
nonwoven fabric structure consisting of three layers structure is
prepared through moistening step and drying step.
6. A method for the preparation of a high moisture absorbent
nonwoven fabric structure, characterized in that a fiber, mixture
mainly containing high moisture absorbent fibers are scattered
continuously on one surface sheet having air permeability on a net,
while sucked from net side to form a moisture-absorbing layer and
then moistening step is applied on the moisture-absorbing layer to
gel the surface of the high moisture absorbent fiber and then
another surface sheet is laminated on it to give a three layers
structure and then it is pressed and dried to adhere the fibers in
the moisture-absorbing layer each other and adhere the
moisture-absorbing layer with the surface sheet.
Description
TECHNICAL FIELD
[0001] The present invention relates to a high moisture absorbent
nonwoven fabric structure. More particularly, it relates to a high
moisture absorbent nonwoven fabric structure which has high
moisture absorption capacity and is suitably used as drying agents
used in transportation of precision parts, dew condensation
preventing agents for industrial equipments, drying agents for
eliminating moisture in bags for confectioneries, demoisturizers
and the like, and its preparation.
BACKGROUND ART
[0002] As electronic parts such as silicon wafers cannot be used
even when slightly rusted, close attention is paid for their
transportation. Electronic parts are put in a tightly closed
container together with a drying agent for transportation as they
are apt to rust when the humidity comes higher. As the drying
agent, silica gel is mainly used at present. Though silica gel can
be recycled by heat treatment, it has problems of heat treating
cost and breakage of particles during heat treatment. Hence, the
silica gel drying agent is usually discarded after use. Though
incineration or reclamation is used as the discarding method, the
treatment shall be performed in a large amount and various problems
such as incineration cost or lack of land to be reclaimed arise and
thus materials easily reusable are desired.
[0003] Though silica gel has been used for dew condensation
prevention of industrial equipment in almost all cases, silica gel
has a disadvantage of bulkiness as it is used in particle form. On
the other hand, miniaturization of dew condensation inhibitor is
desired accompanied to miniaturization of equipment.
[0004] Silica gel and deliquescent salts such as calcium chloride
are used as the drying agent and dehumidifying agent for
confectioneries. Although they are disposed as non-inflammable
refuse in average home, there are problems such as lack of land to
be reclaimed and thus reduction in quantity is desired. Further,
deliquescent salts become liquid by moisture absorption and are in
danger of leaking from packing papers and in addition in danger of
generating heat when water is added to cause a burn.
[0005] On the other hand, the moisture absorbent nonwoven fabric is
commonly prepared by a procedure in which high moisture absorbent
fibers are mixed with other synthetic fibers and/or natural fibers
and carded and needle-punched. However, the high moisture absorbent
fiber is low in fiber strength and fibers are fell off highly
during the manufacturing process at a higher mixing rate and
further twine round the machine as they absorb moisture during the
manufacturing process disadvantageously. Particularly, the high
moisture absorbent fiber of the type wherein the surface gels by
absorbing water and/or moisture has low fiber strength and the
mixing rate is limited to about 40 weight %.
[0006] Other methods for the preparation of moisture absorbent
nonwoven fabrics include air laid method. However, in this method,
it is required to mix heat fusion welding fibers to adhere the
fibers with each other or to adhere the fiber layers with the
surface sheets and also it is required to increase the mixing rate
of heat fusion welding fibers for keeping the shape.
[0007] The present invention has been made in consideration of the
above circumstance and its object is to provide a high moisture
absorbent nonwoven fabric which can be easily recycled after use
and its preparation method.
DISCLOSURE OF THE INVENTION
[0008] We, inventors, have eagerly investigated to solve the above
problem and, as the results, have invented the high moisture
absorbent nonwoven fabric of the present invention. Thus, the high
moisture absorbent nonwoven fabric structure of the present
invention is a high moisture absorbent nonwoven fabric structure
consisting of a three layers structure comprising a
moisture-absorbing layer consisting mainly of high moisture
absorbent fibers and surface sheets with the moisture-absorbing
layer between and it is characterized in the following (a) to
(f).
[0009] (a) Surface of said high moisture absorbent fiber gels by
absorbing water and/or moisture to express self-adhering
activity.
[0010] (b) The fibers in the moisture-absorbing layer adhere each
other and the moisture-absorbing layer and the surface sheets
adhere each other by the self-adhering activity of the high
moisture absorbent fiber.
[0011] (c) At least one of the surface sheets has air
permeability.
[0012] (d) The thickness of the high moisture absorbent nonwoven
fabric structure is not more than 1.5 mm.
[0013] (e) The water content of the high moisture absorbent
nonwoven fabric structure is 20 to 45 weight %. (
[0014] f) The moisture-absorbing rate of the high moisture
absorbent nonwoven fabric structure is at least 20 weight % under
absolute dry condition at 20.degree. C. and 65% RH after 5
hours.
[0015] A preferred embodiment of the high moisture absorbent
nonwoven fabric structure is a high moisture absorbent nonwoven
fabric structure in which the moisture-absorbing layer consists
only of high moisture absorbent fibers. More preferably, the high
moisture absorbent fibers are of a crosslinked sodium acrylate
type.
[0016] The apparent density of the high moisture absorbent nonwoven
fabric structure is preferably 0.05 to 0.8 g/cm.sup.3.
[0017] Furthermore, the high moisture absorbent nonwoven fabric
structure having a three layers structure is preferably prepared
through a moistening step and a drying step.
[0018] The present invention relating to the method for the
preparation of a high moisture absorbent nonwoven fabric structure
is also characterized in that a fiber mixture mainly containing
high moisture absorbent fibers are scattered continuously on one
surface sheet having air permeability on a net while sucked from
net side to form a moisture-absorbing layer, and then a moistening
step is applied on the moisture-absorbing layer to gel the surface
of the high moisture absorbent fiber and then another surface sheet
is laminated on it to give a three layers structure and then it is
pressed and dried to adhere the fibers in the moisture-absorbing
layer each other and adhere the moisture-absorbing layer with the
surface sheets.
BEST MODE FOR CARRYING OUT THE INVENTION
[0019] The high moisture absorbent fiber used in the
moisture-absorbing layer of the present invention should be such
one that the surface gels by absorbing water and/or moisture.
Because, when the high moisture absorbent fiber is such one that
the surface gels by absorbing water and/or moisture, self-adhering
activity is expressed and the fibers in the moisture-absorbing
layer adhere each other and the moisture-absorbing layer and the
surface sheet adhere each other by the self-adhering activity, and
hence any thermal bonding fiber is not required and a higher mixing
rate of the high moisture absorbent fibers comes to be Possible.
When the high moisture absorbent fiber does not gel, self-adhering
activity is not expressed and the fibers in the moisture-absorbing
layer do not adhere each other and the moisture adhering layer and
the surface sheet do not adhere each other and the shape cannot be
kept.
[0020] The high moisture absorbent nonwoven fabric structure of the
present invention shall be of a three layers structure comprising a
moisture-absorbing layer and surface sheets with the
moisture-absorbing layer between. If the moisture-absorbing layer
is exposed on the surface, the high moisture absorbent fibers fall
off during production and no stable production can be made.
[0021] The material and the shape of the surface sheet used in the
present invention are not especially restricted but it is required
that a sheet having air permeability is used in at least one side.
As the sheet having air permeability, for example, paper sheets
such as tissue paper, cloths such as woven and knitted fabrics and
nonwoven fabrics, and perforated non-air-permeable films can be
used. As the non-air-permeable sheet, a film can be used. The
material for surface sheet is preferably one containing no harmful
material such as chlorine from the viewpoint of discarding after
use.
[0022] When sheets having air permeability are used for the both
sides of the surface sheet, the moisture-absorbing rate is higher.
When a sheet having air permeability is used for one side, the
moisture-absorbing surface can be limited to one side. The
moisture-absorbing rate can be varied at will by varying properly
the air permeability of the air-permeable sheet. When
non-air-permeable sheets are used for the both sides, the high
moisture absorbent fibers come to not be able to absorb
moisture.
[0023] The thickness of the high moisture absorbent nonwoven fabric
structure of the present invention is required to be not more than
1.5 mm. When the thickness is as thin as not more than 1.5 mm, it
can be used in a small gap. It is preferably 0.2 mm to 1.2 mm, more
preferably 0.3 mm to 1.0 mm.
[0024] The moisture content of the high moisture absorbent nonwoven
fabric structure of the present invention is required to be 20 to
45 weight %. Though the nonwoven fabric structure is rolled for
transportation and storage, the nonwoven fabric structure comes
rigid when the moisture content is lower than 20 weight % to cause
cracking when rolled. On the other hand, when the moisture content
exceeds 45 weight %, the nonwoven fabric structure comes heavier
and softer and the thickness and the weight per unit area are in
danger of being changed due to its dead load during transportation
and storage. At a moisture content of 20 to 45 weight %, it has
proper pliancy and there is no danger of changing the thickness and
weight per unit area. It is preferably 30 to 40 weight
[0025] Though the high moisture absorbent nonwoven fabric structure
can be used as it is, it is preferred to be used after dried to a
favorite moisture content according to the purpose of use. The
drying method is not particularly restricted. For example, there
may be exemplified methods using a hot air drier, a vacuum drier, a
hand drier or the like.
[0026] The moisture-absorbing rate of the high moisture absorbent
nonwoven fabric structure of the present invention shall be at
least 20 weight % under an absolute dry condition at 20.degree. C.,
65% RH for 5 hours. Preferably, it is at least 30 weight % under
the same condition. When the moisture-absorbing rate is at least 20
weight %, a sufficient performance can be attained as a drying
agent or a moisture-removing agent.
[0027] Though the mixing rate of the high moisture absorbent fibers
used in the moisture-absorbing layer of the present invention is
not defined, it is preferably at least 80 weight %. It is
particularly preferred to be a moisture-absorbing layer consisting
of high moisture absorbent fibers alone.
[0028] As the high moisture absorbent fiber in which the surface
gels by absorbing water and/or moisture, fibers of cross-slinked
sodium acrylate type are exemplified. As the practical example,
there is exemplified "BELLOASIS" made by Kanebo Gohsen, Ltd. The
fiber has a moisture-absorbing rate of 40 weight % at 20.degree.
C., 65% RH and also has excellent properties of high
moisture-absorbing velocity and moisture-releasing velocity.
[0029] The high moisture absorbent fiber swells by containing water
in a large amount and the fiber surface gels to form mutually a
pseudo-adhesion state. Then, the self adhesion between high
moisture absorbent fibers is kept by removing water by drying.
[0030] Also, the apparent density of the high moisture absorbent
nonwoven fabric structure of the present invention is preferably
0.05 to 0.8 g/cm.sup.3. More preferably, it is 0.15 to 0.5
g/cm.sup.3. At an apparent density of 0.05 to 0.8 g/cm.sup.3, it is
good in form-retaining and excellent in moisture-absorption.
[0031] The high moisture absorbent nonwoven fabric structure of the
present invention having three layers structure is preferably
prepared through a moistening step and a drying step.
[0032] The moistening step means a step in which water and/or vapor
is absorbed in the high moisture absorbent fibers to make gel of
the surface of the high moisture absorbent fibers. When water is
used in the moistening step, it is more preferred to give a sucking
step immediately after the moistening step.
[0033] The drying step in the present invention means a step in
which water absorbed in the moistening step is removed and the gel
portion of the high moisture absorbent fibers are restored to the
original condition to adhere the fibers in the moisture-absorbing
layer mutually and adhere the moisture-absorbing layer with the
surface sheets. As the drying means, there are exemplified a
heating furnace, a hot air drier and heating roller, and it is
preferred to dry at 80 to 150.degree. C.
[0034] Now, the method for the preparation of the high moisture
absorbent nonwoven fabric of the present invention will be
illustrated.
[0035] In the manufacturing method of the present invention, a
surface sheet having air permeability is placed on a net and a
fiber mixture mainly containing high moisture absorbent fibers are
scattered continuously on the surface sheet while sucked from net
side to form a moisture-absorbing layer. Then, water and/or vapor
is absorbed (moistening step is applied ) on the moisture-absorbing
layer to induce gelation of the surface of the high moisture
absorbent fibers. Then, another surface sheet is laminated on it to
give a three layers structure and then it is pressed and dried to
adhere the fibers in the moisture-absorbing layer each other and
adhere the moisture-absorbing layer with the surface sheet to give
a high moisture absorbent nonwoven fabric structure.
[0036] When water is used in the moistening step, it is preferred
to carry out a step of sucking from lower side immediately after
the moistening step. Or, it is preferred water is scattered from
the lower side to improve adhesion to the lower surface sheet.
EXAMPLES
[0037] Now, the present invention will be illustrated in details by
Examples and Comparative Examples as follows.
[0038] The test method for moisture-absorbing rate is shown as
follows.
[0039] (Test for Moisture-absorbing Rate
[0040] A sample was dried in a hot air drier at 120 .degree. C. for
2 hours and stood in an air-conditioned chamber at 20.degree. C.
and 65% RH for 5 hours and then the moisture-absorbing rate was
calculated by the following equation.
Moisture-absorbing rate (%)=(W.sub.1-W.sub.0)/W.sub.0.times.100
[0041] W.sub.0; Weight of the nonwoven fabric immediately after
drying (g)
[0042] W.sub.1; Weight of the nonwoven fabric after moisture
absorption (g)
Example 1
[0043] A super water and moisture absorbent fiber "BELLOASIS" of 10
dtex, 6 mm made by Kanebo Gohsen, Ltd. was continuously scattered
uniformly on a tissue having a weight per unit area of 14 g/m.sup.2
on a suction net by air laid method and laminated to make a sheet
of 200 g/m.sup.2. Then, water was sprayed in the state of mist on
the moisture-absorbing layer and then a tissue of 14 g/m.sup.2 was
laminated on the moisture-absorbing layer to give a three layers
structure. It was passed through a press roll to adjust the
thickness to 1.0 mm and then dried in a hot air drier at
130.degree. C. The resultant nonwoven fabric had a weight per unit
area of 228 g/m.sup.2, a thickness of 1.0 mm, a moisture content of
38 weight % and an apparent density of 0.228 g/cm.sup.3.
[0044] The moisture-absorbing layer of this sample was adhered by
self-adhering activity of "BELLOASIS" and the moisture-absorbing
layer was adhered to the tissue of the surface sheet by
"BELLOASIS". The moisture-absorbing rate of the high moisture
absorbent nonwoven fabric structure was 35 weight %. The high
moisture absorbent nonwoven fabric structure was dried at
120.degree. C. for 2 hours and the moisture-absorbing rate was
again measured to be 35 weight %.
Example 2
[0045] The fiber "BELLOASIS" 10 of dtex, 6 mm was scattered
continuously on a spunbonded nonwoven fabric "Eleves" of 15
g/m.sup.2 made by Unitika, Ltd. on a suction net uniformly by air
laid method and laminated to make a sheet of 150 g/m.sup.2. Then,
steam was blown on the moisture-absorbing layer and "Eleves" of 15
g/m.sup.2 was laminated on the moisture-absorbing layer to give a
three layers structure and it was passed through a press roll to a
thickness of 0.7 mm and dried in a hot air drier at 130.degree. C.
The resultant nonwoven fabric had a weight per unit area of 180
g/m.sup.2, a thickness of 0.7 mm, a water content of 30 weight %
and an apparent density of 0.26 g/cm.sup.3.
[0046] The moisture-absorbing layer of this sample was adhered by
self-adhering activity of "BELLOASIS" and the moisture-absorbing
layer was adhered to the surface sheet "Eleves" by "BELLOASIS". The
moisture-absorbing rate of the high moisture absorbent nonwoven
fabric structure was 33 weight %. The highly moisture absorbent
nonwoven fabric structure was dried at 120.degree. C. for 2 hours
and the moisture-absorbing rate was again measured to be 31 weight
%.
Example 3
[0047] The fiber "BELLOASIS" of 10 dtex, 6 mm was scattered
continuously on "Eleves" of 15 g/m.sup.2 on a suction net uniformly
by air laid method and laminated to make a sheet of 150 g/m.sup.2.
Then, water was sprayed in the state of mist on the
moisture-absorbing layer and a polypropylene film of 20 g/m.sup.2
was laminated on the moisture-absorbing layer to give a three
layers structure and it was passed through a hot press roll to a
thickness of 1.0 mm and dried in a hot air drier at 130.degree. C.
The resultant nonwoven fabric had a weight per unit area of 185 g/m
.sup.2, a thickness of 1.0 mm, a water content of 40 weight % and
an apparent density of 0.185 g/cm.sup.3.
[0048] The moisture-absorbing layer of this sample was adhered by
self-adhering activity of "BELLOASIS" and the moisture-absorbing
layer was adhered to the surface sheet "Eleves" by "BELLOASIS" and
the moisture-absorbing layer was also adhered to the polypropylene
film by "BELLOASIS". The moisture-absorbing rate of the high
moisture absorbent nonwoven fabric structure was 32 weight %. The
high moisture absorbent nonwoven fabric structure was dried at
120.degree. C. for 2 hours and the moisture-absorbing rate was
again measured to be 31 weight %.
Example 4
[0049] The fiber "BELLOASIS" of 10 dtex, 6 mm was scattered
continuously on a tissue of 14 g/m.sup.2 on a suction net uniformly
by air laid method and laminated to make a sheet of 300 g/m.sup.2.
Then, water was sprayed in the state of mist on the
moisture-absorbing layer and a tissue of 14 g/m.sup.2 was laminated
on the moisture-absorbing layer to give a three layers structure
and it was passed through a press roll to a thickness of 0.8 mm and
dried in a hot air drier at 120.degree. C. The resultant nonwoven
fabric had a weight per unit area of 328 g/m.sup.2, a thickness of
0.8 mm, a water content of 39 weight % and an apparent density of
0.410 g/cm.sup.3.
[0050] The moisture-absorbing layer of this sample was adhered by
self-adhering activity of "BELLOASIS" and the moisture-absorbing
layer was adhered to the surface sheet "Eleves" by "BELLOASIS" and
the moisture-absorbing layer was also adhered to the tissue of the
surface sheet by "BELLOASIS". The moisture-absorbing rate of the
high moisture absorbent nonwoven fabric structure was 36 weight %.
The high moisture absorbent nonwoven fabric structure was dried at
120.degree. C. for 2 hours and the moisture-absorbing rate was
again measured to be 36 weight %.
Example 5
[0051] 80 weight % of the fiber "BELLOASIS" of 10 dtex, 6 mm and 20
weight % of conifer pulp were scattered continuously on a tissue of
14 g/m.sup.2 on a suction net uniformly by air laid method and
laminated to make a sheet of 200 g/m.sup.2. Then, water was sprayed
in the state of mist on the moisture-absorbing layer and a tissue
of 14 g/m.sup.2 was laminated on the moisture-absorbing layer to
give a three layers structure and it was passed through a press
roll to a thickness of 0.6 mm and dried in a hot air drier at
120.degree. C. The resultant nonwoven fabric had a weight per unit
area of 228 g/m.sup.2, a thickness of 0.6 mm, a water content of 45
weight % and an apparent density of 0.380 g/cm.sup.3.
[0052] The moisture-absorbing layer of this sample was adhered by
self-adhering activity of "BELLOASIS" and the moisture-absorbing
layer was adhered to the surface sheet "Eleves" by "BELLOASIS" and
the moisture-absorbing layer was also adhered to the tissue of the
surface sheet by "BELLOASIS". The moisture-absorbing rate of the
high moisture absorbent nonwoven fabric structure was 29 weight %.
The high moisture absorbent nonwoven fabric structure was dried at
120.degree. C. for 2 hours and the moisture-absorbing rate was
again measured to be 28 weight %.
Comparative Example 1
[0053] 50 weight % of the fiber "BELLOASIS" of 10 dtex, 6 mm and 50
weight % of conifer pulp were scattered continuously on a tissue of
14 g/m.sup.2 on a suction net uniformly by air laid method and
laminated to make a sheet of 200 g/m.sup.2. Then, water was sprayed
in the state of mist on the moisture-absorbing layer and a tissue
of 14 g/m.sup.2 was laminated on the moisture-absorbing layer to
give a three layers structure and it was passed through a press
roll to a thickness of 1.0 mm and dried in a hot air drier at
130.degree. C. The resultant nonwoven fabric had a weight per unit
area of 228 g/m.sup.2, a thickness of 1.0 mm, a water content of 35
weight % and an apparent density of 0.228 g/cm.sup.3.
[0054] Though the moisture-absorbing layer of this sample was
adhered by self-adhering activity of "BELLOASIS", the adhering
activity was weak. Also, though the moisture-absorbing layer was
adhered to the tissue of the surface sheet by "BELLOASI", the
adhering activity was weak. Furthermore, the moisture-absorbing
rate of the high moisture absorbent fabric structure was as low as
18 weight %.
Comparative Example 2
[0055] A super moisture absorbent fiber "N-38" of 4.4 dtex, 6 mm
made by Toyobo Co., Ltd. was scattered continuously on a tissue of
40 g/m.sup.2 on a suction net uniformly by air laid method and
laminated to a web of 200 g/m.sup.2. Then the web was stood at
30.degree. C. and 90% RH for 10 minutes to wet "N-38" and then a
tissue of 40 g/m.sup.2 was laminated on the moisture-absorbing
layer to give a three layers structure. It was passed through a
press roll to a thickness of 1.0 mm and dried in a hot air drier at
130.degree. C. "N-38" did not gel though moistened and no nonwoven
fabric could be prepared.
[0056] Industrial Applicability The high moisture absorbent
nonwoven fabric structure of the present invention contains the
high moisture absorbent fibers in a high mixing rate and therefore
it is high in hygroscopicity and can be used in a small space as it
is very thin. Furthermore, as it can be easily recycled by
heat-treating the nonwoven fabric after moisturized, it can be used
in various fields including drying agents and dehumidifying
agents.
* * * * *