U.S. patent application number 16/976121 was filed with the patent office on 2020-12-31 for antistatic dustproof fabric and protective clothing using same.
This patent application is currently assigned to Toray Industries, Inc.. The applicant listed for this patent is Toray Industries, Inc.. Invention is credited to Yuichiro Hayashi, Yu Shibata, Jie Xu.
Application Number | 20200404986 16/976121 |
Document ID | / |
Family ID | 1000005103648 |
Filed Date | 2020-12-31 |
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United States Patent
Application |
20200404986 |
Kind Code |
A1 |
Shibata; Yu ; et
al. |
December 31, 2020 |
ANTISTATIC DUSTPROOF FABRIC AND PROTECTIVE CLOTHING USING SAME
Abstract
A dustproof fabric which includes an antistatic dustproof fabric
having excellent antistatic properties, a high air permeability and
high-level dustproof properties is provided. The antistatic
dustproof fabric includes two or more fiber layers. At least one of
the two or more fiber layers is a first fiber layer which contains
a nonionic antistatic agent; and at least one of the two or more
fiber layers is a second fiber layer which is electrically
charged.
Inventors: |
Shibata; Yu; (Otsu-shi,
Shiga, JP) ; Hayashi; Yuichiro; (Otsu-shi, Shiga,
JP) ; Xu; Jie; (Nantong, Jiangsu, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Toray Industries, Inc. |
Tokyo |
|
JP |
|
|
Assignee: |
Toray Industries, Inc.
Tokyo
JP
|
Family ID: |
1000005103648 |
Appl. No.: |
16/976121 |
Filed: |
February 25, 2019 |
PCT Filed: |
February 25, 2019 |
PCT NO: |
PCT/JP2019/006976 |
371 Date: |
August 27, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A41D 31/265 20190201;
D06M 15/53 20130101; D06M 15/507 20130101; A41D 2600/20 20130101;
A41D 13/008 20130101 |
International
Class: |
A41D 13/008 20060101
A41D013/008; D06M 15/53 20060101 D06M015/53; D06M 15/507 20060101
D06M015/507; A41D 31/26 20060101 A41D031/26 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 9, 2018 |
JP |
2018-042686 |
Claims
1. An antistatic dust-prevention fabric comprising at least two or
more fiber layers, wherein at least one layer, which is defined as
fiber layer 1, of these two or more fiber layers comprises a
nonionic antistatic agent, and at least another layer, which is
defined as fiber layer 2, of these two or more fiber layers being
in an electrified state.
2. The antistatic dust-prevention fabric of claim 1, wherein the
nonionic antistatic agent is a polymer type nonionic antistatic
agent.
3. The antistatic dust-prevention fabric of claim 1, having an air
permeability of 60 cm.sup.3/cm.sup.2/sec or more as measured by the
Frazier method according to JIS L1913-2010 and a dust collection
efficiency of 50% or more.
4. The antistatic dust-prevention fabric of claim 1, wherein the
fiber layer 1 is disposed at least as either of the outermost
layers of the antistatic dust-prevention fabric.
5. Protective clothing comprising the antistatic dust-prevention
fabric of claim 1.
6. The protective clothing of claim 5, wherein the fiber layer 1 is
exposed in at least a portion of either outer surface of the
antistatic dust-prevention fabric.
Description
[0001] This is the U.S. National Phase application of
PCT/JP2019/006976, filed Feb. 25, 2019, which claims priority to
Japanese Patent Application No. 2018-042686, filed Mar. 9, 2018,
the disclosures of these applications being incorporated herein by
reference in their entireties for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates to an antistatic dust
protective fabric and protective clothing formed thereof.
BACKGROUND OF THE INVENTION
[0003] Conventionally, in operations to remove dust and chemicals
or to handle dust and chemicals, workers often wear protective
clothing, rubber gloves, rubber boots, and dust masks (hereinafter
occasionally referred to as protective items) on top of clothing.
These protective items are currently adopted in diversified
environments including clean rooms where, for example, they are
used to prevent dust from being raised by personnel during
manufacturing of electronic components. On the other hand,
electronic components are known to fail due to static electricity
and therefore, for the purpose of preventing static electricity
from being generated by abrasion of clothing of workers during
their production, some clothing products for these workers have
antistatic-treated surfaces. In addition, some protective clothing
for workers engaged in removal, handling, etc. of dust and
chemicals have antistatic-treated surfaces for the purpose of
suppressing the adsorption of dust and chemicals due to static
electricity and suppressing the occurrence of explosions due to
static electricity.
[0004] Here, Patent document 1 discloses an improved nonwoven
barrier and a method for manufacture thereof and proposes a
laminate composed of a first and a second nonwoven web that are
charged with electricity or treated with an antistatic material. It
is disclosed that the combined use of such an electrified web and
an antistatic-treated web serves to realize a higher average cell
filtration efficiency (BFE) compared to cases where only uncharged
webs are used. Specifically, it is shown that the filtration
efficiency to remove fine particles such as bacteria and dust is
improved by using a charged web.
[0005] In addition, Patent document 2, which discloses a protective
clothing material and protective clothing, proposes protective
clothing made of a protective clothing material having at least one
surface treated with an antistatic agent in order to prevent fine
particles such as dust from adhering to the protective clothing or
prevent an explosion from being caused by static generation, and
describes that a laminate sheet having an antistatic-treated
spunbonded nonwoven fabric surface had an electrostatic surface
resistivity of 1.5.times.10.sup.10.OMEGA. as measured according to
JIS K 6911.
PATENT DOCUMENTS
[0006] Patent document 1: International Publication WO 96/00093
Patent document 2: Japanese Unexamined Patent Publication (Kokai)
No. 2003-166106 Patent document 3: Published Japanese Translation
of PCT International Publication JP 2011-522137
[0007] Patent document 1 discloses that a laminate composed of an
electrified web and an antistatic-treated web has an improved
average cell filtration efficiency because of the existence of the
charged web. However, as disclosed in Patent document 3, it is
known that an antistatic agent works to weaken the charging effect
as it receives the charged electricity from the charged web or
increases its conductivity, and in the case of the invention
proposed in Patent document 1, therefore, it is expected that the
average cell filtration efficiency improving effect of the charged
electricity, that is, the effect of adsorbing dust and chemical
substances, is unstable. Regarding the antistatic agent used for
this invention, furthermore, no preferred examples of the
antistatic agent are shown, indicating that no considerations are
given to deterioration in charging performance that may be caused
by such an antistatic agent.
[0008] Patent document 2 discloses protective clothing formed of a
protective clothing material in which at least one surface is
antistatic-treated and gives preferred examples of antistatic
agents including nonionic substances such as polyoxyethylene alkyl
ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene
alkylamine, and polyoxyethylene fatty acid ester. In the invention
disclosed in Patent document 2, however, the protection against
harmful substances such as harmful gases and harmful dust is
realized by using sheets of synthetic resins such as
polyacrylonitrile-based resin and ethylene vinyl alcohol
copolymers, and it is expected that protective clothing materials
that contain these synthetic resin sheets are so low in air
permeability that protective clothing according to this invention,
when worn, is poor in comfortability during work.
[0009] Accordingly, in view of the above circumstances, an object
of the present invention is to provide an antistatic
dust-prevention fabric having high levels of antistatic property,
air permeability, and dust-prevention property.
SUMMARY OF THE INVENTION
[0010] To solve the problem, the present invention provides an
antistatic dust-prevention fabric as described below:
(1) An antistatic dust-prevention fabric including at least two or
more fiber layers, at least one layer, which is defined as fiber
layer 1, of these two or more fiber layers containing a nonionic
antistatic agent, and at least another layer, which is defined as
fiber layer 2, of these two or more fiber layers being in an
electrified state. (2) An antistatic dust-prevention fabric as set
forth in (1), wherein the nonionic antistatic agent is polymer type
nonionic antistatic agent. (3) An antistatic dust-prevention fabric
as set forth in either (1) or (2) having an air permeability of 60
cm.sup.3/cm.sup.2/sec or more as measured by the Frazier method
according to JIS L1913-2010 and a dust collection efficiency of 50%
or more. (4) An antistatic dust-prevention fabric as set forth in
any one of (1) to (3), wherein the fiber layer 1 is disposed at
least as either of the outermost layers. (5) Protective clothing
including an antistatic dust-prevention fabric as set forth in any
one of (1) to (4). (6) Protective clothing as set forth in (5),
wherein the fiber layer 1 is exposed in part of either outer
surface.
[0011] The present invention serves to provide an antistatic
dust-prevention fabric having high levels of antistatic property,
air permeability, and dust-prevention property.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 A conceptual cross-sectional view of the first
embodiment of the antistatic dust-prevention fabric of the present
invention
[0013] FIG. 2 A conceptual cross-sectional view of the second
embodiment of the antistatic dust-prevention fabric of the present
invention
[0014] FIG. 3 A conceptual SEM image of the antistatic
dust-prevention fabric
[0015] FIG. 4 A conceptual view illustrating the interaction
between fibers present in the fiber layer 1 and a nonionic
antistatic agent
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0016] The antistatic dust-prevention fabric according to the
present invention and protective clothing including the antistatic
dust-prevention fabric are described in detail below.
[0017] The antistatic dust-prevention fabric according the present
invention includes at least two or more fiber layers, wherein at
least one layer, which is defined as fiber layer 1, of these two or
more fiber layers contains a nonionic antistatic agent, and at
least another layer, which is defined as fiber layer 2, of these
two or more fiber layers is in an electrified state.
[0018] The fiber layer 1 and the fiber layer 2 may be stacked in
direct contact with each other, or other layers may be present
between the fiber layer 1 and the fiber layer 2 unless they impair
the preferred effects of the present invention. Here, it is
preferable that the fiber layer 1 and the fiber layer 2 are in
direct contact with each other in a stack because it serves to
produce an antistatic dust-prevention fabric having a higher air
permeability and also because the number of steps in the production
process for the antistatic dust-prevention fabric can be reduced to
realize a higher productivity in the production of the antistatic
dust-prevention fabric. Here, structural examples of such a stack
in which the fiber layer 1 and the fiber layer 2 are in direct
contact include a structure in which the fiber layer 1 and the
fiber layer 2 are directly combined through the entanglement of
constituent fibers of each fiber layer that is realized by needle
punching, etc., and a structure in which the fiber layer 1 and the
fiber layer 2 are directly combined using an adhesive such as hot
melt adhesive.
[0019] The fact that the fiber layer 1 contains a nonionic
antistatic agent while the fiber layer 2 is an electrified layer
serves to realize both an antistatic effect due to the fiber layer
1 and a high dust collecting efficiency due to the electrostatic
charge on the fiber layer 2.
[0020] Here, it is presumed that the mechanism of deterioration in
electrification performance of the fiber layer 2 that is disposed
adjacent to the fiber layer 1 containing an antistatic agent is as
follows.
[0021] First, in the case where the polarity of the antistatic
agent is the same as that of the zeta potential of the fibers
present the fiber layer 1, the antistatic agent is transferred into
the fiber layer 2 that is located adjacent to the fiber layer 1 due
to the strong repulsive interaction between the antistatic agent
and the fibers in the fiber layer 1. As a result, the antistatic
agent transferred into the fiber layer 2 will work to capture the
static charges from the fiber layer 2 or increase its conductivity,
leading to a decline in the electrification effect on the fiber
layer 2. It should be noted that the strong repulsive interaction
means a strong repulsive force.
[0022] Therefore, in the case where the fiber layer 1 contains a
nonionic antistatic agent while the fiber layer 2 is an electrified
layer, the fact that the antistatic agent is a nonionic antistatic
agent serves to prevent a strong repulsive interaction from being
generated between the nonionic antistatic agent and the fibers
present in the fiber layer 1 regardless of whether the zeta
potential of the fibers present in the fiber layer 1 has a positive
polarity or a negative polarity. Thus, the nonionic antistatic
agent is unlikely to move easily from the fiber layer 1 into the
fiber layer 2, thus preventing the loss of electric charges on the
fiber layer 2.
[0023] Furthermore, it is presumed that, in addition to suppressing
the occurrence of a strong repulsive interaction between the
nonionic antistatic agent and the fibers present in the fiber layer
1, the following mechanism also contributes to the prevention of
deterioration in the electrification performance of the fiber layer
2. The mechanism is described below with reference to FIG. 4.
Specifically, it can be assumed that the fiber 12 present in the
fiber layer 1 substantially contains charges corresponding to the
polarity of the zeta potential of the fibers 12. Then, the charge
in the fiber 12 located closest to the nonionic antistatic agent 13
acts to cause dielectric polarization inside the molecule of the
nonionic antistatic agent 13. Thus, the following occurs in the
case shown in FIG. 4. The fiber 12 located closest to the nonionic
antistatic agent 13 has a negative charge. Due to this negative
charge, positive charges 16, which have the opposite polarity to
the negative charge, are substantially generated in a portion of
the nonionic antistatic agent 13 close to the fiber 12, whereas
negative charges 17, which have the same polarity as the above
negative charge, are substantially generated in a portion of the
nonionic antistatic agent 13 far from the fiber 12. Then, an
attractive force occurs between charges having opposite polarities,
whereas a repulsive force occurs between charges having the same
polarity. Here, since the distance 14 between the negative charge
in the fiber 12 and the positive charge 16 is shorter than the
distance 15 between the negative charge in the fiber 12 and the
negative charge 17, the fiber 12 and the nonionic antistatic agent
13 are affected more strongly by the attractive force than by the
repulsive force. It is presumed that, as a result, an attractive
interaction occurs between the fiber 12 and the nonionic antistatic
agent 13, and that this attractive interaction acts to prevent the
nonionic antistatic agent from moving from the fiber layer 1 into
the fiber layer 2, thereby suppressing the loss of charges from the
fiber layer 2.
[0024] FIG. 4 illustrates a case in which the charge corresponding
to the polarity of the zeta potential of the fiber 12 is negative,
but it is expected that the same effect as described above can be
realized in the opposite case in which the charge corresponding to
the polarity of the zeta potential of the fiber 12 is positive,
although the charges in the vicinity of the nonionic antistatic
agent 13 will have the opposite polarities.
[0025] Regarding the numbers of the fiber layer 1 and the fiber
layer 2, the resulting fabric may contain one fiber layer 1 and one
fiber layer 2, totaling two fiber layers, or two of either type
layer may be included. The antistatic property can be enhanced by
using a larger number of fiber layer 1s while the dust collection
efficiency can be increased by using a larger number of fiber layer
2s. Specifically, an antistatic dust-prevention fabric may contain,
for example, a laminate of two layers consisting of a fiber layer 1
and a fiber layer 2, or a laminate consisting of a fiber layer 1, a
fiber layer 2, and a fiber layer 1 stacked in this order.
[0026] In the case of an antistatic dust-prevention fabric
including a plurality of layers, it is preferable that a fiber
layer 1 is disposed as the outermost layer on either side of the
fabric. If the antistatic dust-prevention fabric has the fiber
layer 1 containing a nonionic antistatic agent as the outermost
layer, it allows the outermost layer to be high in electrostatic
surface resistivity, which is an indicator of antistatic
performance.
[0027] The fiber layer 1 and the fiber layer 2 are described in
detail below.
[Fiber Layer 1]
[0028] Examples of the fiber used to form the fiber layer 1 present
in the antistatic dust-prevention fabric according to the present
invention include polyolefins such as polyethylene and
polypropylene, polyesters such as polyethylene terephthalate and
polylactic acid, others such as polycarbonates, fluorine-based
resins, cellulose, wool, silk, nylon, and mixtures thereof. Of
these, polyolefins are preferred from the viewpoint of high
productivity in antistatic dust-prevention fabric production and
good texture of the resulting antistatic dust-prevention fabrics,
and among other polyolefins, polypropylene is particularly
preferred from the viewpoint of high mechanical strength.
[0029] Good materials for the fiber layer 1 include woven fabrics,
knitted fabrics, and nonwoven fabrics, of which nonwoven fabrics
are preferred from the viewpoint of high productivity in producing
the fiber layer 1. Various nonwoven fabrics are available
including, for example, spun lace nonwoven fabrics, spunbonded
nonwoven fabrics, melt blown nonwoven fabrics, and needle punched
nonwoven fabrics, of which spunbonded nonwoven fabrics are
preferred because of high productivity in fiber layer production as
well as high strength and high air permeability.
[0030] The fiber layer 1 contains a nonionic antistatic agent. As
described above, if the antistatic agent present in the fiber layer
1 is a nonionic antistatic agent, it serves to allow the fiber
layer 2 to maintain its electrified state. Examples of the nonionic
antistatic agent include generally known nonionic antistatic agents
that contain ether compounds, polyhydric alcohol ether compounds,
ester compounds, polyhydric alcohol ester compounds, or the like as
main components. In particular, a polymer type nonionic antistatic
agent is preferred from the viewpoint of longer antistatic
performance retention after abrasion, and a polymer type nonionic
antistatic agent containing an ester compound is preferred from the
viewpoint of reducing the electrostatic surface resistivity, which
is an indicator of antistatic performance.
[0031] For the antistatic finishing of the fiber layer 1,
conventionally known techniques can be used unless the preferred
effects of the present invention are impaired. For example, the
fiber layer 1 may be subjected to immersion treatment in a
treatment liquid containing an antistatic component, or an
antistatic agent may be kneaded into the fiber used to form the
fiber layer 1 so that the fiber itself will have antistatic
property. The fiber layer 1 may be coated with a coating liquid
containing an antistatic component to make it antistatic. In
particular, the immersion based antistatic finishing technique is
preferred because it commonly ensures high productivity and a small
electrostatic surface resistivity which represents good antistatic
property.
[0032] It is preferable for the fiber layer 1 to have 0.1% by mass
or more of deposited antistatic agent. The amount is more
preferably 0.7 mass or more. If it is 0.1% by mass or more, it
serves to realize a small electrostatic surface resistivity which
is an indicator of antistatic property. Although there are no
particular limitations on the upper limit of the amount of the
deposited antistatic agent in the fiber layer 1, it is practically
preferably 10% by mass or less because the electrostatic surface
resistivity will not be improved as the amount of the antistatic
agent exceeds a certain level.
[0033] As regards the antistatic performance of the fiber layer 1,
it is preferable for the electrostatic surface resistivity to be
5.0.times.10.sup.12.OMEGA. or less as measured according to
EN1149-1-2006. If the electrostatic surface resistivity of the
fiber layer 1 is 5.0.times.10.sup.12.OMEGA. or less, it serves to
prevent the fiber layer 1 from being electrified as it comes in
contact with or is abraded by another fiber layer 1 or other
objects. To realize a preferred electrostatic surface resistivity
value, there are known techniques that can be used unless the
preferred effects of the present invention are impaired, including,
for example, the use of an increased amount of deposited antistatic
agent, which works to reduce the electrostatic surface
resistivity.
[Fiber Layer 2]
[0034] It is necessary for the fiber layer 2 present in the
antistatic dust-prevention fabric according to the present
invention to be in an electrified state. Because of being
electrified, the fiber layer 2 will have higher dust collection
performance.
[0035] For the electrification of the fiber layer 2, conventionally
known techniques can be used unless the preferred effects of the
present invention are impaired, and for example, the fiber layer 2
can be charged by corona electrification, frictional
electrification, water flow electrification, or the like.
[0036] It is preferable that a melt blown nonwoven fabric produced
by a melt blowing process is used as the fiber layer 2. In a common
melt blowing process, a thermoplastic polymer extruded through
spinning nozzles is exposed to a hot air jet to produce finely
split fibers and a web is formed by means of the self-welding
characteristics of the fibers. Major items of spinning conditions
for a melt blowing process include polymer discharge rate, nozzle
temperature, and air pressure, and the optimization of the spinning
conditions serves to produce a nonwoven fabric having an intended
fiber diameter. The use of a melt-blown nonwoven fabric as the
fiber layer 2 makes it possible to provide an antistatic
dust-prevention fabric that has a high dust collecting efficiency
and air permeability when incorporating an electrified fiber
layer.
[0037] From the viewpoint of, for example, productivity and
electrification performance, good materials for the fiber layer 2
present in the antistatic dust-prevention fabric according to the
present invention include those containing a polyolefin based resin
as main component although various conventionally known techniques
may be adopted unless the preferred effects according to the
present invention are impaired. Of the various polyolefin based
resins, polypropylene is particularly preferred from the viewpoint
of easily improving the dust collecting performance of the fiber
layer 2 by electrification. Here, the expression "the fiber layer 2
contains a polyolefin based resin as main component" means that, as
described above, the polyolefin-based resin present in the fiber
layer 2 accounts for 80% by mass or more of the entire fiber layer
2. Furthermore, it is preferable that the polyolefin-based resin
present in the fiber layer 2 accounts for 90% by mass or more of
the entire fiber layer 2, and it is more preferable that the fiber
layer 2 is formed only of a polyolefin-based resin.
[0038] It is preferable that the antistatic dust-prevention fabric
according to the present invention has an air permeability of 60
cm.sup.3/cm.sup.2/sec or more as measured by the Frazier method
according to JIS L1913-2010 and that the antistatic dust-prevention
fabric at the same time has a dust collection efficiency of 50% or
more. When the antistatic dust-prevention fabric has both a high
air permeability and a high dust collection efficiency, it will be
possible to achieve both high comfortability and high
dust-prevention performance. The air permeability and dust
collection efficiency of the antistatic dust-prevention fabric is
described more specifically below.
[0039] When the air permeability of the antistatic dust-prevention
fabric is 60 cm.sup.3/cm.sup.2/sec or more, the replacement of air
will occur smoothly between one side and the opposite side of the
antistatic dust-prevention fabric and accordingly, if the
antistatic dust-prevention fabric is used as a filter, it serves
for efficient replacement of air between one side and the opposite
side. If the antistatic dust-prevention fabric is used as material
for chemical protective clothing, efficient replacement of air will
occur between the wearer and the outside through the antistatic
dust-prevention fabric in the chemical protective clothing so that
increases in the temperature and humidity inside the chemical
protective clothing can be prevented to ensure high comfortability.
Although there is no upper limit on the air permeability of the
antistatic dust-prevention fabric, air permeability is generally a
physical property having the opposite effect to the dust collecting
efficiency so that the dust collecting efficiency tends to decrease
as the air permeability increases, and practically, therefore, it
is preferably 200 cm.sup.3/cm.sup.2/sec or less to maintain the
dust collecting efficiency of the antistatic dust-prevention fabric
in a desirable range.
[0040] To control the air permeability of the antistatic
dust-prevention fabric in a desirable range, a practical method is
to adjust the thickness and average fiber diameter of the fiber
layer 1 and fiber layer 2 within appropriate ranges. Specifically,
the air permeability can be decreased by decreasing the average
fiber diameter or increasing the thickness of the fiber layer 1 or
the fiber layer 2, whereas the air permeability can be increased by
increasing the average fiber diameter or decreasing the thickness
of the fiber layer 1 or the fiber layer 2.
[0041] It is preferable for the antistatic dust-prevention fabric
according to the present invention to have a dust collecting
efficiency of 50% or more. When the dust collecting efficiency of
the antistatic dust-prevention fabric is 50% or more, the passage
of dust can be suppressed efficiently as air containing dust passes
through the antistatic dust-prevention fabric. Although the dust
collecting efficiency of the antistatic dust-prevention fabric can
be 100% at maximum, dust collecting efficiency is generally a
physical property having the opposite effect to air permeability,
as described above, so that the air permeability tends to decrease
as the dust collecting efficiency increases, and practically,
therefore, it is 95% or less to maintain the air permeability of
the antistatic dust-prevention fabric in a desirable range.
[0042] To control the dust collecting efficiency of the antistatic
dust-prevention fabric in a desirable range, a practical method is
to adjust the thickness and average fiber diameter of the fiber
layer 2, which is electrified, within appropriate ranges.
Specifically, the dust collecting efficiency can be increased by
decreasing the average fiber diameter or increasing the thickness
of the fiber layer 2, whereas the dust collecting efficiency can be
decreased by increasing the average fiber diameter or decreasing
the thickness of the fiber layer 2.
[0043] The antistatic dust-prevention fabric according to the
present invention may have a third layer other than the fiber layer
1 and the fiber layer 2. The third layer may be, for example, a
fiber layer, perforated film, perforated metal foil, or the like
unless the preferred effects according to the present invention are
impaired, and it may be the same as the fiber layer 1. Furthermore,
the third layer may be either a single layer or a combination of a
plurality of layers.
[0044] The third layer may have special functions unless the
preferred effects according to the present invention are impaired,
and may have such functions as water repellency, oil repellency,
flame retardancy, bacteria elimination, and mold inhibition.
[0045] When a third layer is present, it is preferable that the
fiber layer 1 is disposed as the outermost layer on either side. If
the antistatic dust-prevention fabric has the fiber layer 1
containing a nonionic antistatic agent as the outermost layer, it
allows the outermost layer of the antistatic dust-prevention fabric
to be high in electrostatic surface resistivity, which is an
indicator of antistatic performance.
[0046] The antistatic dust-prevention fabric according the present
invention can serve as material for chemical protective clothing.
The inclusion of the antistatic dust-prevention fabric in chemical
protective clothing serves to prevent the electrification of the
surface of the chemical protective clothing during work to ensure
comfortability due to high air permeability and dust-prevention
performance due to high dust collection efficiency.
[0047] When using the antistatic dust-prevention fabric according
the present invention as material for chemical protective clothing,
it is preferable that the fiber layer 1 is exposed at least in a
portion of either outer surface. If the fiber layer 1 containing a
nonionic antistatic agent is arranged so that it is exposed at
least in a portion of either outer surface, it allows the chemical
protective clothing to have high electrostatic surface resistivity,
which is an indicator of antistatic performance.
[0048] There are various methods for stacking the fiber layer 1,
fiber layer 2, and third layer to form an antistatic
dust-prevention fabric that can be adopted unless good features of
the present invention are not impaired, and useful ones include
ultrasonic bonding, thermal bonding using a thermal embossing roll
having a pattern height of 1 mm or more, and pasting with an
adhesive, which can serve to prevent the fiber layer 1 and the
fiber layer 2 from melting or fusing beyond a desired degree due to
excessive heat. Of these, pasting with an adhesive is particularly
preferred in order to ensure uniform adhesion in the regions where
the fiber layer 1, fiber layer 2, and third layer are in contact
with each other.
EXAMPLES
[0049] The invention is described in more detail below with
reference to Examples.
[Measuring Methods]
(1) Dust Collection Efficiency
[0050] The dust collection efficiency of an antistatic
dust-prevention fabric was measured by using a collection
performance measuring device. The collection performance measuring
device has a sample holder to hold a sample for measurement along
with a dust storage box connected on its upstream side and a flow
rate meter, a flow rate adjusting valve, and a blower connected on
its downstream side. In addition, the sample holder is equipped
with a particle counter that has a switch cock to measure the
number of dust particles on the upstream side and the number of
dust particles on the downstream side of the measuring sample. The
sample holder is also equipped with a pressure gage to measure the
difference in static pressure between the upstream side and the
downstream side of the sample.
[0051] To determine the dust collection efficiency, the dust
storage box was filled with standard latex powder of polystyrene
having a diameter of 0.3 .mu.m (a 10% by mass solution of 0.309 U
polystyrene manufactured by Nacalai Tesque, Inc., diluted 200 times
with distilled water) and the sample was set in the sample holder,
followed by controlling the air feed rate by the flow rate
adjusting valve so as to adjust the filter passing speed to 3
m/min, stabilizing the dust concentration in the range of 10,000 to
40,000 per 2.83.times.10.sup.-4 m3 (0.01 ft.sup.3), leave the
equipment for 30 seconds after stabilization was reached, taking
three measurements of the number of dust particles D on the
upstream side and the number of dust particles d on the downstream
side of the sample using a particle counter (KC-01E, manufactured
by Rion Co., Ltd.), and calculating the dust collection efficiency
(%) from the averages of the three measurements each of the number
of dust particles D and the number of dust particles d by the
following equation. Measurements were taken by this procedure from
10 samples, and the dust collection efficiency values of the 10
samples were averaged.
Dust collection efficiency (%)=[1-(d/D)].times.100
The dust collection efficiency values of the 10 samples were
averaged.
(2) Dust Collection Efficiency Retention Rate
[0052] After determining its collection efficiency by the method
described in (1), the antistatic dust-prevention fabric was
sandwiched between two expanded polystyrene sheets having a size of
200 mm.times.200 mm and a thickness of 1 cm, and left to stand for
14 days under a load of 6 kg in an environment at 35% RH and
60.degree. C. as an accelerated test. After the 14 day period, the
antistatic dust-prevention fabric subjected to the accelerated test
was taken out into an environment at 23.degree. C., and left to
stand for 24 hours, followed by calculating the collection
efficiency retention rate (%) by the equation of "the collection
efficiency B/the collection efficiency A.times.100", wherein the
collection efficiency A is the collection efficiency before the
accelerated test while the collection efficiency B is the
collection efficiency after the accelerated test determined by the
collection efficiency measuring procedure described in paragraph
(2). After taking measurements by this procedure from five samples,
the dust collection efficiency retention rate measurements of the
five samples were averaged and rounded off to the nearest whole
number, followed by rating the fabric as A when its dust collection
efficiency retention rate was 60% or more, or B when it is less
than 60%, wherein A means "acceptable".
(3) Air Permeability
[0053] To represent the air permeability of an antistatic
dust-prevention fabric, the rate of air flow passing through a
specimen having a size of 15 cm.times.15 cm was measured by the
Frazier method according to JIS L1913-2010. The rate of air flow
was measured three times and the measurements was averaged to
represent the air permeability.
(4) Electrostatic Surface Resistivity
[0054] For the measurement of the electrostatic surface resistivity
of an antistatic dust-prevention fabric, a specimen having a size
of 12 cm.times.12 cm was prepared and the electrostatic surface
resistivity of the fiber layer 1 was measured according to
EN1149-1-2006.
(5) Electrostatic Surface Resistivity after Abrasion
[0055] Measurement of the electrostatic surface resistivity after
abrasion of an antistatic dust-prevention fabric was performed as
follows: a 12 cm wide piece of cotton fabric as specified in JIS
L0803 was fixed to a support of 12 cm.times.12 cm and 1 kg and used
to rub the fiber layer 1 of a test piece having a size of 12
cm.times.12 cm at a rate of one time per second, and rubbing was
performed a total of 300 times while replacing the cotton fabric
every 10 times, followed by determining the electrostatic surface
resistivity of the resulting test piece as specified in paragraph
(4) Electrostatic surface resistivity.
(6) Agent Deposition Rate
[0056] From an antistatic dust-prevention fabric, the layers other
than the fiber layer 1 were removed using No. 1000 sandpaper. A 15
cm.times.15 cm specimen was cut out of the resulting fiber layer 1
and the mass of the fiber layer 1 specimen was measured in grams to
five decimal places. After measuring its mass, the fiber layer 1
specimen was put in a beaker containing 100 ml of methanol, and
extraction by ultrasonic waves was performed for 10 minutes. The
extract solution obtained by ultrasonic cleaning was dried at
40.degree. C. until it was concentrated to 1 ml, and then filtered
through a 0.45 .mu.m PTFE disk filter, and the filtrate containing
the extract was diluted 10 times and then examined by an LC/MS/MS
apparatus (LC20A, manufactured by Shimadzu Corporation). The
antistatic agent in use was identified from the results obtained
and the area of the peak attributed to the antistatic agent
identified was calculated. For the calculation of the agent
deposition rate, materials having the same composition as the
antistatic agent identified from the fiber layer 1 were newly
prepared and diluted 10 times, 100 times, or 1,000 times, with
methanol to provide diluted solutions, which were examined in the
same manner as for the extract-containing filtrate. The peak areas
attributed to the antistatic agent identified above were
calculated, and a calibration curve was formed from the amounts of
the antistatic agent identified and the peak areas calculated. The
peak area determined from the solvent extraction liquid of the
fiber layer 1 was compared with the calibration curve, and the
amount of the antistatic agent deposited on the fiber layer 1 was
calculated and divided by the mass of the fiber layer 1 measured in
advance to give a quotient, which was rounded off to one decimal
place and adopted as the agent deposition rate (mass %) of the
fiber layer 1.
(7) Thickness
[0057] The antistatic dust-prevention fabric was cut with a
microtome to expose a section perpendicular to the surface of the
antistatic dust-prevention fabric. The cross-section of the
antistatic dust-prevention fabric thus prepared was photographed at
a magnification of 200 times under a field emission type scanning
electron microscope (FE-SEM) (S-800, manufactured by Hitachi,
Ltd.). At this time, photographing was performed so that the length
direction of the image to obtain would be substantially
perpendicular to the thickness direction of the antistatic
dust-prevention fabric shown in the image. Here, a conceptual
diagram illustrating the SEM image of the cross-section of the
antistatic dust-prevention fabric is given in FIG. 3. The procedure
for measuring the thickness of each layer constituting the
antistatic dust-prevention fabric is described below with reference
to FIG. 3. The conceptual diagram of the SEM image given FIG. 3
depicts the cross-section of the antistatic dust-prevention fabric,
which includes the fiber layer 1 2 and the fiber layer 2 3, and
background 6. First, in the SEM image, five dividing lines 7 were
drawn which are perpendicular to the length direction of the SEM
image and equally divides the width in the length direction of the
SEM image into six. Then, the length of the section of each
dividing line running across the fiber layer 1 2 was measured (an
example of the dividing line running across the fiber layer 1 is
numbered 8 in FIG. 3). Also, the length of the section of each
dividing line running across the fiber layer 2 3 was measured (an
example of the dividing line running across the fiber layer 2 is
numbered 9 in FIG. 3). At this time, for the measurement of the
lengths of the above dividing lines, the length of each dividing
line was read to one decimal place in micrometers and rounded off
to the nearest whole number. The above measuring procedure was
performed on 10 SEM images taken from different portions of the
cross section of the antistatic dust-prevention fabric to obtain 50
measurements of the lengths of the dividing lines running across
the fiber layer 1, which were averaged to represent the thickness
of the fiber layer 1. Then, 50 measurements of the lengths of the
dividing lines running across the fiber layer 2 were taken and
averaged to represent the thickness of the fiber layer 2. Here, in
the case where there was a portion 10 (i.e., a portion where no
fibers were seen in the photograph) which appeared to be a cavity
at the boundary between the fiber layer 1 and the fiber layer 2 in
the SEM image and where this cavity-like portion includes a
dividing line, the cavity-like portion was assumed to be part of
the fiber layer 2 when measuring the length of the section of the
dividing line running across the fiber layer 2 and the length of
the section of the dividing line running across the fiber layer 1.
Accordingly, in the example given in FIG. 3, the section numbered
12 represents the length of the dividing line 7 running across the
fiber layer 2 3 and the section numbered 11 represents the length
of the dividing line 7 running across the fiber layer 1 2. Here,
when the antistatic dust-prevention fabric further included a third
layer, the thickness of the third layer was measured by the same
measuring procedure as for the measurement of the thickness of the
fiber layer 1 described above.
(8) Average Fiber Diameter
[0058] To further examine the antistatic dust-prevention fabric, a
cross-section of the antistatic dust-prevention fabric prepared by
the procedure described in (7) Thickness was photographed at
magnifications of 500 times and 1000 times under a field emission
type scanning electron microscope (FE-SEM) (S-800, manufactured by
Hitachi, Ltd.). These image data were fed into the image analysis
program provided with the equipment. Here, for fibers having fiber
diameters of less than 10 .mu.m, SEM images taken at a
magnification of 500 times were used to determine their fiber
diameters, whereas for fibers having fiber diameters of 10 .mu.m or
more, SEM images taken at a magnification of 1,000 times were used
to determine their fiber diameters. More specifically, from the
fiber layer 1 photographed in a SEM image, 15 fibers contained in
this fiber layer 1 were randomly selected, and the fiber diameters
of these fibers were measured. Then, the average of the 15
measurements thus taken was calculated to represent the average
fiber diameter of the fibers in the fiber layer 1. In addition,
from the fiber layer 2 photographed in a SEM image, 15 fibers
contained in this fiber layer 2 were randomly selected, and the
fiber diameters of these fibers were measured. Then, the average of
the 15 measurements thus taken was calculated to represent the
average fiber diameter of the fibers in the fiber layer 2. Here,
for the fiber diameter measurement, the fiber diameter was read to
one decimal place in micrometers and rounded off to the nearest
whole number. Furthermore, when the antistatic dust-prevention
fabric further included a third layer and this third layer was
formed mainly of fibers, the average fiber diameter of the third
layer was determined by the same measuring procedure as for the
measurement of the average fiber diameter of the fiber layer 1
described above.
[0059] Preparation of the antistatic dust-prevention fabric was
carried out as follows.
Example 1
[0060] A spunbonded nonwoven fabric A1 was formed using a
spunbonded nonwoven fabric and an antistatic agent. For the
antistatic treatment, Meika finish SRM-65, manufactured by Meisei
Chemical Works, Ltd., was used as an antistatic agent, and normal
hexanol was used as a penetrating agent. They were mixed in pure
water according to the formula A specified in Table 2 and subjected
to dipping treatment and mangling treatment. The mangled spunbond
was dried at 135.degree. C. for 1 minute in a pin tenter.
[0061] After the antistatic treatment of the spunbonded nonwoven
fabric A1, an adhesive (Moresco-Melt (registered trademark)
TN-367Z, manufactured by Moresco Corporation), which was melted by
heating at 150.degree. C., was sprayed through a T-die by a hot
melt adhesion machine over the first surface of the spunbonded
nonwoven fabric A1 to a coating weight of 2 g/m.sup.2. The adhesive
applied in this step was found to be dispersed in a spotted pattern
over the first surface of the spunbonded nonwoven fabric A1.
Subsequently, the electrified meltblown nonwoven fabric B1 was
bonded to the first surface of the spunbonded nonwoven fabric A1.
The resulting two-layered sheet composed of the spunbonded nonwoven
fabric A 1 and the meltblown nonwoven fabric B1 was wound up to
provide the antistatic dust-prevention fabric of Example 1. The
zeta potential, agent deposition rate, average fiber diameter,
thickness, constituent fiber material, etc. of the fiber layer 1
present in the resulting antistatic dust-prevention fabric are
shown in Table 1. In addition, the average fiber diameter,
thickness, constituent fiber material, etc. of the fiber layer 2
present in the resulting antistatic dust-prevention fabric are
shown in Table 1. Furthermore, the layer structure, collection
efficiency, collection efficiency retention rate, electrostatic
surface resistivity, electrostatic surface resistivity after
abrasion, and air permeability of the resulting antistatic
dust-prevention fabric of Example 1 are shown in Table 3.
Examples 2 to 4
[0062] Except for using an antistatic agent according to the
formula B, C, or D, the same procedure as in Example 1 was carried
out to combine a spunbonded nonwoven fabric and an antistatic agent
to provide spunbonded nonwoven fabrics A2 to A4. Except for
replacing the spunbonded nonwoven fabric A1 with the spunbonded
nonwoven fabrics A2 to A4, the same procedure as in Example 1 was
carried out to provide the antistatic dust-prevention fabrics of
Examples 2 to 4. For the resulting spunbonded nonwoven fabrics A2
to A4, the agent deposition rate, average fiber diameter, and
thickness are shown in Table 1. Furthermore, the layer structure,
collection efficiency, collection efficiency retention rate,
electrostatic surface resistivity, electrostatic surface
resistivity after abrasion, and air permeability of the antistatic
dust-prevention fabrics of Examples 2 to 4 are shown in Table
3.
Examples 5 to 7
[0063] The same procedure as in Example 1 was carried out to
combine a spunbonded nonwoven fabric and an antistatic agent to
provide spunbonded nonwoven fabrics A5 to A7. Except for replacing
the spunbonded nonwoven fabric A1 with the spunbonded nonwoven
fabrics A5 to A7, the same procedure as in Example 1 was carried
out to provide the antistatic dust-prevention fabrics of Examples 5
to 7. For the resulting spunbonded nonwoven fabrics A5 to A7, the
agent deposition rate, average fiber diameter, and thickness are
shown in Table 1. Furthermore, the layer structure, collection
efficiency, collection efficiency retention rate, electrostatic
surface resistivity, electrostatic surface resistivity after
abrasion, and air permeability of the antistatic dust-prevention
fabrics of Examples 5 to 7 are shown in Table 3.
Example 8
[0064] In the same manner as in Example 1, the spunbonded nonwoven
fabric A1 and the electrified meltblown nonwoven fabric B1 were
combined to provide an antistatic dust-prevention fabric. For the
resulting antistatic dust-prevention fabric composed of the
spunbonded nonwoven fabric A1 and the electrified meltblown
nonwoven fabric B1, an adhesive (Moresco-Melt (registered
trademark) TN-367Z, manufactured by Moresco Corporation), which was
melted by heating at 150.degree. C., was sprayed through a T-die by
a hot melt adhesion machine over the surface of the meltblown
nonwoven fabric to a coating weight of 2 g/m.sup.2. The adhesive
applied in this step was found to be dispersed in a spotted pattern
over the first surface of the meltblown nonwoven fabric B1.
Subsequently, the spunbonded nonwoven fabric A9 was bonded to the
first surface of the electrified spunbonded nonwoven fabric B1. The
resulting three-layered sheet composed of the spunbonded nonwoven
fabric A1, the meltblown nonwoven fabric B1, and the spunbonded
nonwoven fabric A9 was wound up to provide the antistatic
dust-prevention fabric of Example 8. For the resulting spunbonded
nonwoven fabrics A1 and A9, the agent deposition rate, average
fiber diameter, and thickness are shown in Table 1. Furthermore,
the layer structure, collection efficiency, collection efficiency
retention rate, electrostatic surface resistivity, electrostatic
surface resistivity after abrasion, and air permeability of the
antistatic dust-prevention fabrics of Examples 8 are shown in Table
3.
Examples 9 to 12
[0065] Except for replacing the electrified meltblown nonwoven
fabric B1 with the electrified meltblown nonwoven fabrics B2 to B5,
the same procedure as in Example 1 was carried out to provide the
antistatic dust-prevention fabrics of Examples 9 to 12. The average
fiber diameter and thickness of the resulting meltblown nonwoven
fabrics B2 to B5 are shown in Table 1. Furthermore, the layer
structure, collection efficiency, collection efficiency retention
rate, electrostatic surface resistivity, electrostatic surface
resistivity after abrasion, and air permeability of the antistatic
dust-prevention fabrics of Examples 9 to 12 are shown in Table
3.
Comparative Example 1
[0066] Except for replacing the antistatic agent used in Example 1
with an antistatic agent according to the formula E, the same
procedure as in Example 1 was carried out to combine a spunbonded
nonwoven fabric and an antistatic agent to provide a spunbonded
nonwoven fabric A8. In addition, except for using the spunbonded
nonwoven fabric A8 instead of the spunbonded nonwoven fabric A1,
the same procedure as in Example 1 was carried out to provide the
antistatic dust-prevention fabric of Comparative example 1. For the
resulting spunbonded nonwoven fabric A8, the agent deposition rate,
average fiber diameter, and thickness are shown in Table 1.
Furthermore, the layer structure, collection efficiency, collection
efficiency retention rate, electrostatic surface resistivity,
electrostatic surface resistivity after abrasion, and air
permeability of the antistatic dust-prevention fabrics Comparative
example 1 are shown in Table 3.
Comparative Example 2
[0067] Except for omitting the antistatic treatment step, the same
procedure as in Example 1 was carried out to provide a spunbonded
nonwoven fabric A9 using only a spunbonded nonwoven fabric. In
addition, except for using the spunbonded nonwoven fabric A9
instead of the spunbonded nonwoven fabric A1, the same procedure as
in Example 1 was carried out to provide the layered fiber stack of
Comparative example 2. For the resulting spunbonded nonwoven fabric
A9, the agent deposition rate, average fiber diameter, and
thickness are shown in Table 1. Furthermore, the layer structure,
collection efficiency, collection efficiency retention rate,
electrostatic surface resistivity, electrostatic surface
resistivity after abrasion, and air permeability of the layered
fiber stack of Comparative example 2 are shown in Table 3.
Comparative Example 3
[0068] The spunbonded nonwoven fabric A9 was adopted here, and an
adhesive (Moresco-Melt (registered trademark) TN-367Z, manufactured
by Moresco Corporation), which was melted by heating at 150.degree.
C., was sprayed through a T-die by a hot melt adhesion machine over
the first surface of the spunbonded nonwoven fabric A9 to a coating
weight of 2 g/m.sup.2. The adhesive applied in this step was found
to be dispersed in a spotted pattern over the first surface of the
spunbonded nonwoven fabric A9. Subsequently, the electrified
meltblown nonwoven fabric B1 was bonded to the first surface of the
spunbonded nonwoven fabric A9. The resulting two-layered sheet
composed of the spunbonded nonwoven fabric A9 and the meltblown
nonwoven fabric B1 was wound up. For the resulting antistatic
dust-prevention fabric composed of the spunbonded nonwoven fabric
A9 and the electrified meltblown nonwoven fabric B1, an adhesive
(Moresco-Melt (registered trademark) TN-367Z, manufactured by
Moresco Corporation), which was melted by heating at 150.degree.
C., was sprayed through a T-die by a hot melt adhesion machine over
the surface of the meltblown nonwoven fabric to a coating weight of
2 g/m.sup.2. The adhesive applied in this step was found to be
dispersed in a spotted pattern over the first surface of the
meltblown nonwoven fabric B1. Subsequently, the spunbonded nonwoven
fabric A1 was bonded to the first surface of the electrified
spunbonded nonwoven fabric B1. The resulting three-layered sheet
composed of the spunbonded nonwoven fabric A9, the meltblown
nonwoven fabric B1, and the spunbonded nonwoven fabric A1 was wound
up. Furthermore, for the resulting antistatic dust-prevention
fabric composed of the spunbonded nonwoven fabric A9, the
electrified meltblown nonwoven fabric B1, and the spunbonded
nonwoven fabric A1, an adhesive (Moresco-Melt (registered
trademark) TN-367Z, manufactured by Moresco Corporation), which was
melted by heating at 150.degree. C., was sprayed through a T-die by
a hot melt adhesion machine over the surface of the spunbonded
nonwoven fabric A1 to a coating weight of 2 g/m.sup.2. The adhesive
applied in this step was found to be dispersed in a spotted pattern
over the first surface of the spunbonded nonwoven fabric A1.
Subsequently, another layer of the spunbonded nonwoven fabric A9
was bonded to the first surface of the spunbonded nonwoven fabric
A1. The resulting four-layered sheet composed of the spunbonded
nonwoven fabric A9, the meltblown nonwoven fabric B1, the
spunbonded nonwoven fabric A1, and the spunbonded nonwoven fabric
A9 was wound up to provide the antistatic dust-prevention fabric of
Comparative example 3. The layer structure, collection efficiency,
collection efficiency retention rate, electrostatic surface
resistivity, electrostatic surface resistivity after abrasion, and
air permeability of the antistatic dust-prevention fabric of
Comparative example 3 are shown in Table 3.
Comparative Example 4
[0069] Except for replacing the electrified meltblown nonwoven
fabric B1 with the unelectrified meltblown nonwoven fabric B6, the
same procedure as in Example 1 was carried out to provide the
antistatic dust-prevention fabric of Comparative example 4. The
average fiber diameter and thickness of the meltblown nonwoven
fabric B6 prepared are shown in Table 1. Furthermore, the layer
structure, collection efficiency, collection efficiency retention
rate, electrostatic surface resistivity, electrostatic surface
resistivity after abrasion, and air permeability of the antistatic
dust-prevention fabric of Comparative example 4 are shown in Table
3.
TABLE-US-00001 TABLE 1 Constituent Antistatic Zeta Agent deposition
Fiber diameter Thickness Form of fiber fiber material agent
potential rate (mass %) (.mu.m) (.mu.m) Electrification Fiber layer
1 spunbonded polypropylene formula A negative 1.6 20 150 -- (A)
nonwoven fabric A1 spunbonded polypropylene formula B negative 3.3
20 150 -- nonwoven fabric A2 spunbonded polypropylene formula C
negative 0.2 20 150 -- nonwoven fabric A3 spunbonded polypropylene
formula D negative 2.2 20 150 -- nonwoven fabric A4 spunbonded
polypropylene formula A negative 1.5 18 150 -- nonwoven fabric A5
spunbonded polypropylene formula A negative 1.7 30 150 -- nonwoven
fabric A6 spunbonded polypropylene formula A negative 1.6 18 300 --
nonwoven fabric A7 spunbonded polypropylene formula E negative 1.8
20 150 -- nonwoven fabric A8 spunbonded nylon 6 formula A positive
1.4 20 150 -- nonwoven fabric A9 spunbonded polypropylene --
negative 0 20 150 -- nonwoven fabric A10 Fiber layer 2 meltblown
polypropylene -- -- -- 3 120 electrified (B) nonwoven fabric B1
meltblown polypropylene -- -- -- 1 120 electrified nonwoven fabric
B2 meltblown polypropylene -- -- -- 6 120 electrified nonwoven
fabric B3 meltblown polypropylene -- -- -- 3 80 electrified
nonwoven fabric B4 meltblown polypropylene -- -- -- 3 250
electrified nonwoven fabric B5 meltblown polypropylene -- -- -- 3
120 unelectrified nonwoven fabric B6
TABLE-US-00002 TABLE 2 Penetrating Antistatic agent agent
Concentration Concentration Type (mass %) Category (g/L) Formula A
Meika Finish SRM-65, 5 high molecular 2 manufactured by Meisei
nonionic Chemical Works Formula B Meika Finish SRM-65, 15 high
molecular 2 manufactured by Meisei nonionic Chemical Works Formula
C Meika Finish SRM-65, 0.5 high molecular 2 manufactured by Meisei
nonionic Chemical Works Formula D Sanstat AA, 5 low molecular 2
manufactured by Meisei nonionic Chemical Works Formula E Delectol
MAP, 5 low molecular 2 manufactured by Meisei anion Chemical
Works
TABLE-US-00003 TABLE 3 Electrostatic Collection Electrostatic
surface Air Collection efficiently surface resistivity permeability
Layer constituents efficiently retention resistivity after abrasion
(cm.sup.3/cm.sup.2/ fiber layer 1 fiber layer 2 fiber layer 3 (%)
rate (%) (.omega.) (.omega.) sec) Example 1 spunbonded meltblown --
-- 83 A 2.5 .times. 10.sup.11 3.2 .times. 10.sup.11 121 nonwoven
nonwoven fabric A1 fabric B1 Example 2 spunbonded meltblown -- --
79 A 4.8 .times. 10.sup.10 3.1 .times. 10.sup.10 120 nonwoven
nonwoven fabric A2 fabric B1 Example 3 spunbonded meltblown -- --
80 A 1.8 .times. 10.sup.12 1.0 .times. 10.sup.12 122 nonwoven
nonwoven fabric A3 fabric B1 Example 4 spunbonded meltblown -- --
81 A 7.5 .times. 10.sup.10 1.8 .times. 10.sup.13 128 nonwoven
nonwoven fabric A4 fabric B1 Example 5 spunbonded meltblown -- --
86 A 2.8 .times. 10.sup.11 1.3 .times. 10.sup.11 105 nonwoven
nonwoven fabric A5 fabric B1 Example 6 spunbonded meltblown -- --
77 A 7.6 .times. 10.sup.11 7.7 .times. 10.sup.11 140 nonwoven
nonwoven fabric A6 fabric B1 Example 7 spunbonded meltblown -- --
86 A 1.8 .times. 10.sup.11 4.0 .times. 10.sup.11 91 nonwoven
nonwoven fabric A7 fabric B1 Example 8 spunbonded meltblown
spunbonded -- 83 A 3.2 .times. 10.sup.11 1.1 .times. 10.sup.11 89
nonwoven nonwoven nonwoven fabric A1 fabric B1 fabric A9 Example 9
spunbonded meltblown -- -- 91 A 2.2 .times. 10.sup.11 5.0 .times.
10.sup.11 43 nonwoven nonwoven fabric A1 fabric B2 Example 10
spunbonded meltblown -- -- 62 A 2.6 .times. 10.sup.11 3.1 .times.
10.sup.11 153 nonwoven nonwoven fabric A1 fabric B3 Example 11
spunbonded meltblown -- -- 75 A 2.9 .times. 10.sup.11 2.9 .times.
10.sup.11 138 nonwoven nonwoven fabric A1 fabric B4 Example 12
spunbonded meltblown -- -- 91 A 3.9 .times. 10.sup.11 1.5 .times.
10.sup.11 45 nonwoven nonwoven fabric A1 fabric B5 Comparative
spunbonded meltblown -- -- 82 B 1.2 .times. 10.sup.8 5.2 .times.
10.sup.11 122 example 1 nonwoven nonwoven fabric A8 fabric B1
Comparative spunbonded meltblown -- -- 80 A <1.0 .times.
10.sup.15 <1.0 .times. 10.sup.15 124 example 2 nonwoven nonwoven
fabric A9 fabric B1 Comparative spunbonded meltblown spunbonded
spunbonded 83 A <1.0 .times. 10.sup.15 <1.0 .times. 10.sup.15
84 example 3 nonwoven nonwoven nonwoven nonwoven fabric A9 fabric
B1 fabric A1 fabric A9 Comparative spunbonded meltblown -- -- 25 A
2.5 .times. 10.sup.11 1.1 .times. 10.sup.11 120 example 4 nonwoven
nonwoven fabric A1 fabric B6
INDUSTRIAL APPLICABILITY
[0070] The antistatic dust-prevention fabric according the present
invention can serve effectively as material for chemical protective
clothing.
EXPLANATION OF NUMERALS
[0071] 1: Antistatic dust-prevention fabric [0072] 2: Fiber layer 1
[0073] 3: Fiber layer 2 [0074] 4: Fiber layer 3 [0075] 5:
Background [0076] 6: Dividing lines [0077] 7: Length of the
dividing line running across the fiber layer 1 [0078] 8: Length of
the dividing line running across the fiber layer 2 [0079] 9:
Portion appearing to be a cavity [0080] 10: Length of the dividing
line running across the fiber layer 1 [0081] 11: Length of the
dividing line running across the fiber layer 2 [0082] 12: Fiber
present in the fiber layer 1 [0083] 13: Nonionic antistatic agent
[0084] 14: Distance between negative charge and positive charge
[0085] 15: Distance between two negative charges [0086] 16:
Positive charge [0087] 17: Negative charge
* * * * *