U.S. patent application number 12/981372 was filed with the patent office on 2011-04-28 for woven fabric for airbag.
This patent application is currently assigned to Toyo Boseki Kabushiki Kaisha. Invention is credited to Hiroaki Hagiwara, Takahiro Hattori, Hideo Isoda, Kenichiro Kano, Mamoru Kitamura, Gaku Maruyama, Takashi Tsuruta.
Application Number | 20110097955 12/981372 |
Document ID | / |
Family ID | 40717535 |
Filed Date | 2011-04-28 |
United States Patent
Application |
20110097955 |
Kind Code |
A1 |
Kano; Kenichiro ; et
al. |
April 28, 2011 |
WOVEN FABRIC FOR AIRBAG
Abstract
An object of the present invention is to provide a woven fabric
for an airbag which is of low cost, is excellent in
accommodability, and has air permeability satisfying the human body
initial constraining performance. The present invention provides a
woven fabric for an airbag comprising a synthetic fiber woven
fabric having a cover factor represented by the equation 1 of 2000
to 2500 in which at least one side thereof is coated with a
synthetic resin, wherein air permeability of the woven fabric under
a pressure difference of 100 kPa is 0.01 to 1.00 L/cm.sup.2/min,
and a resin film is present at an upper part of a single yarn at a
thickness of 2 .mu.m or less on a central cross section of a
weaving yarn part, while a resin film is present at an upper part
of a single yarn at a thickness of 2 to 30 .mu.m on a cross section
at a border between weaving yarn parts.
Inventors: |
Kano; Kenichiro; (Osaka,
JP) ; Tsuruta; Takashi; (Shiga, JP) ;
Kitamura; Mamoru; (Osaka, JP) ; Isoda; Hideo;
(Shiga, JP) ; Hagiwara; Hiroaki; (Fukui, JP)
; Maruyama; Gaku; (Fukui, JP) ; Hattori;
Takahiro; (Fukui, JP) |
Assignee: |
Toyo Boseki Kabushiki
Kaisha
Osaka
JP
|
Family ID: |
40717535 |
Appl. No.: |
12/981372 |
Filed: |
December 29, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12746384 |
Jun 4, 2010 |
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PCT/JP2008/068726 |
Oct 16, 2008 |
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12981372 |
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Current U.S.
Class: |
442/76 |
Current CPC
Class: |
D06M 15/263 20130101;
D06N 3/121 20130101; Y10T 428/24612 20150115; D06N 3/14 20130101;
D06M 15/568 20130101; Y10T 442/2139 20150401; D06N 3/0002 20130101;
Y10T 442/2811 20150401; D03D 15/46 20210101; D06N 3/125 20130101;
D06M 15/59 20130101; B60R 21/235 20130101; D03D 1/02 20130101; D06N
3/042 20130101; D06M 15/507 20130101; B60R 2021/23514 20130101 |
Class at
Publication: |
442/76 |
International
Class: |
B32B 5/24 20060101
B32B005/24 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 7, 2007 |
JP |
2007-316508 |
Jul 11, 2008 |
JP |
2008-181103 |
Claims
1-7. (canceled)
8. A woven fabric for an airbag comprising a synthetic fiber woven
fabric having a cover factor represented by the equation 1 of 2000
to 2500 in which at least one side thereof is coated with 0.1 to
8.0 g/m.sup.2 of a polyamide-based resin, wherein air permeability
of the woven fabric under a pressure difference of 100 kPa is 0.01
to 1.00 L/cm.sup.2/min, and a resin film is present at an upper
part of a single yarn at a thickness of 2 .mu.m or less on a
central cross section of a weaving yarn part, while a resin film is
present at an upper part of a single yarn at a thickness of 2 to 30
.mu.m on a cross section at a border between weaving yarn parts.
Cover factor = [ warp density ( number / 2.54 cm ) .times. ( warp
fineness ( dtex ) .times. 0.9 ) ] + [ weft density ( number / 2.54
cm ) .times. ( weft fineness ( dtex ) .times. 0.9 ) ] ( equation 1
) ##EQU00003##
9. The woven fabric for an airbag according to claim 8, wherein a
coating amount of the polyamide-based resin is 1.0 to 8.0 g/m.sup.2
in terms of a mass after drying.
10. The woven fabric for an airbag according to claim 8, wherein
the polyamide-based resin is in a form of a resin composition
containing a water-soluble thickener in the polyamide-based resin,
and the woven fabric for an airbag is obtained by coating, on the
synthetic fiber woven fabric, an aqueous dispersion comprising the
resin composition and having a viscosity of 5 to 200 dPas, followed
by drying.
11. The woven fabric for an airbag according to claim 8 wherein the
polyamide-based resin has a polyether compound of a number average
molecular weight of 100 to 5000 as a soft segment.
12. The woven fabric for an airbag according to claim 11, wherein
the polyether compound in the polyamide-based resin is
amino-modified.
13. The woven fabric for an airbag according to claim 11, wherein
the polyamide-based resin is a polyether polyamide copolymer
composed of a soft segment and a hard segment, the soft segment
consists of polyether polyamide composed of a polyether diamine
compound represented by the following general formula (I) and a
dicarboxylic acid compound represented by the following general
formula (II), and the hard segment consists of a polyamide composed
of an aminocarboxylic acid compound represented by the following
general formula (III), and/or a lactam compound represented by the
following general formula (IV). [Chemical formula 1] H.sub.2N R--O
.sub.nR--NH.sub.2 (I) wherein R represents a straight or branched
alkylene group of a carbon number of 2 to 3, and n represents a
numerical value of 13 to 26, [Chemical formula 2]
HOOC--R.sup.1--COOH (II) wherein R.sup.1 represents a tethering
group comprising a hydrocarbon chain, [Chemical formula 3]
H.sub.2N--R.sup.2--COOH (III) wherein R.sup.2 represents a
tethering group comprising a hydrocarbon chain, ##STR00003##
wherein R.sup.3 represents a tethering group comprising a
hydrocarbon chain,
14. The woven fabric for an airbag according to claim 10, wherein
the water-soluble thickener is a cellulose-based derivative.
Description
TECHNICAL FIELD
[0001] The present invention relates to a woven fabric for an
airbag which is of the low cost, and excellent in accommodability,
and has air permeability satisfying a human body initial
constraining performance.
BACKGROUND ART
[0002] An airbag, a wearing rate of which has been rapidly
increased in recent years as one of automobile safety parts, is
such that upon an automobile collision accident, a sensor senses
impact, an inflator generates a gas at a high temperature and a
high pressure, this gas rapidly develops an airbag, thereby, upon
flying of a driver and a passenger in a collision direction,
particularly a head is prevented or protected from colliding
against a handle, a front glass or a door glass. Previously, in the
airbag, a coated woven fabric covered with a synthetic rubber such
as chloroprene, chlorosulfonated olefin and silicone has been used
because of high heat resistance, high air insulating property (low
air permeability), and high flame-retardancy and, currently, a
silicone-coated woven fabric has become the mainstream.
[0003] However, since a woven fabric coated with these synthetic
rubbers is increased in a mass of a woven fabric, is not
satisfactory in flexibility, and is of the high manufacturing cost,
it has many disadvantages for use in a woven fabric for an
airbag.
[0004] It has been previously known that a woven fabric is improved
by a coating amount of a woven fabric (see Patent Literature 1).
However, there is no description in connection with airbag
development performance in Patent Literature 1. Further, air
permeability and burning property are not at a satisfactory level,
and improvement is sought.
[0005] In addition, for the purpose of reduction in a weight, and
cost saving, an invention of coating a woven fabric with a
crosslinking elastomer is provided (see e.g., Patent Literature 2).
However, since an adhesion amount is high in embodiments in Patent
Literature 2, and heat is necessary for crosslinking, this becomes
a factor of cost increase, being not preferable.
[0006] On the other hand, in an airbag for head-on collision, a
non-coated airbag using a woven fabric which is light, is excellent
in accommodability, and is not coated has become the mainstream
(see e.g., Patent Literature 3). However, in an airbag which is of
a small distance from a passenger, such as an airbag for a side
collision, higher speed development performance is necessary and,
for this reason, a woven fabric for an fabric withstanding a high
pressure inflator is sought.
[0007] Currently, as a woven fabric for an airbag which can
maintain lightness, and better accommodability, being properties of
a non-coated woven fabric, impregnation treatment with a synthetic
resin diluent is proposed (see e.g., Patent Literature 4). However,
air permeability of the woven fabric for an airbag obtained by this
method is not sufficiently satisfactory.
[0008] A method of controlling the resin existence state in a woven
fabric, and trying to decrease a weight is also studied (see e.g.,
Patent Literature 5). The method of Patent Literature 5 is aimed at
residence of a large amount of a resin at a "knot part", but there
are problems in that since a resin is also present at a "weaving
yarn part", a resin amount is increased, and in that particularly
when a resin amount is reduced, since a part necessary for
controlling air permeability is not only the "knot part" but also a
border part where a warp and a weft are crossed, air permeability
is high. [0009] Patent Literature 1: JP-A 5-016753 [0010] Patent
Literature 2: JP-A 2001-524624 [0011] Patent Literature 3: JP-A
4-281062 [0012] Patent Literature 4: JP-A 11-222776 [0013] Patent
Literature 5: JP-A 6-8779
DISCLOSURE OF THE INVENTION
Problems to be solved by the Invention
[0014] In view of the circumstances of the Background Art, an
object of the present invention is to provide a woven fabric for an
airbag, which is of the low cost, is excellent in accommodability,
and has air permeability satisfying human body initial constraining
performance.
Means to Solve the Problems
[0015] In order to attain the object, the present invention has the
following features.
(1) A woven fabric for an airbag comprising a synthetic fiber woven
fabric having a cover factor represented by the equation 1 of 2000
to 2500 in which at least one side thereof is coated with a
synthetic resin, wherein air permeability of the woven fabric under
a pressure difference of 100 kPa is 0.01 to 1.00 L/cm.sup.2/min or
less, and a resin film is present at an upper part of a single yarn
at a thickness of 2 .mu.m or less on a central cross section of a
weaving yarn part, while a resin film is present at an upper part
of a single yarn at a thickness of 2 to 30 .mu.m on a cross section
at a border between weaving yarn parts.
Cover factor = [ warp density ( number / 2.54 cm ) .times. ( warp
fineness ( dtex ) .times. 0.9 ) ] + [ weft density ( number / 2.54
cm ) .times. ( weft fineness ( dtex ) .times. 0.9 ) ] ( equation 1
) ##EQU00001##
(2) The woven fabric for an airbag according to (1), wherein a
coating amount of the synthetic resin is 0.1 to 15 g/m.sup.2 in
terms of a mass after drying. (3) The woven fabric for an airbag
according to (1) or (2), wherein the synthetic resin is in a form
of a resin composition containing a water-soluble thickener in at
least one kind of a thermoplastic resin selected from the group
consisting of a polyurethane-based resin, an acryl-based resin, a
polyester-based resin, and a polyamide-based resin, and the woven
fabric for an airbag is obtained by coating, on the synthetic fiber
woven fabric, an aqueous dispersion comprising the resin
composition and having a viscosity of 5 to 200 dPas, followed by
drying. (4) The woven fabric for an airbag according to any one of
(1) to (3), wherein the synthetic resin is a polyamide-based resin
having a soft segment of a number average molecular weight of 100
to 5000. (5) The woven fabric for an airbag according to (4),
wherein the soft segment is amino-modified. (6) The woven fabric
for an airbag according to (4), wherein the polyamide-based resin
is a polyether polyamide copolymer composed of a soft segment and a
hard segment, the soft segment consists of polyether polyamide
composed of a polyether diamine compound represented by the
following general formula (I) and a dicarboxylic acid compound
represented by the following general formula (II), and the hard
segment consists of a polyamide composed of an aminocarboxylic acid
compound represented by the following general formula (III), and/or
a lactam compound represented by the following general formula
(IV).
[Chemical Formula 1]
[0016] H.sub.2 NR--O .sub.nRNH.sub.2 (I)
[wherein R represents a straight or branched alkylene group of a
carbon number of 2 to 3, and n represents a numerical value of 13
to 26] [Chemical formula 2]
HOOC--R.sup.1--COOH (II)
[wherein R.sup.1 represents a tethering group comprising a
hydrocarbon chain] [Chemical formula 3]
H.sub.2N--R.sup.2--COOH (III)
[wherein R.sup.2 represents a tethering group comprising a
hydrocarbon chain]
##STR00001##
[wherein R.sup.3 represents a tethering group comprising a
hydrocarbon chain] (7) The woven fabric for an airbag according to
(3), wherein the thickener is a cellulose-based derivative.
EFFECT OF THE INVENTION
[0017] The woven fabric for an airbag of the present invention is
of the low cost, is excellent in accommodability, and can have air
permeability satisfying the initial of a human body constraining
performance, since a coated synthetic resin is made to be
selectively present on a cross section at a border between weaving
yarn parts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is an SEM photograph of a surface of one example of
the synthetic fiber woven fabric before coating of the synthetic
resin in the present invention.
[0019] FIG. 2 is an SEM photograph of a cross section B of FIG.
1.
[0020] FIG. 3 is an SEM photograph of a cross section A of FIG.
1.
BEST MODE FOR CARRYING OUT THE INVENTION
[0021] The present invention will be explained in detail below.
[0022] The synthetic fiber used in the present invention is not
particularly limited in a material, but aliphatic polyamide fibers
such as nylon 66, nylon 6, nylon 46, nylon and the like, aromatic
polyamide fibers such as an aramide fiber, and polyester fibers
such as polyethylene terephthalate, polytrimethylene terephthalate
and polybutylene terephthalate are used. Other examples include
wholly aromatic polyester fibers, ultrahigh molecular weight
polyethylene fibers, polyparaphenylene/benzobisoxazole fibers (PBO
fiber), polyphenylene sulfide fibers, polyether ketone fibers and
the like. In view of economy, polyester fibers and polyamide fibers
are particularly preferable. In addition, as these fibers, a part
or all of them may be obtained from a used raw material. In
addition, it is not problematic at all that these synthetic fibers
contain various additives in order to improve step passage property
at an original yarn production step and a post-possessing step.
Examples of additives include antioxidants, thermal stabilizers,
smoothing agents, antistatic agents, viscosity increasing agents,
flame-retardants and the like. In addition, it is not problematic
at all that these synthetic fibers are a colored original yarn, or
are dyed after yarn-making. In addition, a cross section of a
single yarn of the synthetic fiber may be of a modified
cross-section in addition to a conventional circular cross section
without any problem. It is preferable that the synthetic fiber is
used as a multifilament yarn and woven into a fabric from a
viewpoint of a breakage strength, a breakage elongation or the
like.
[0023] In the present invention, a method of weaving a fabric is
not particularly limited, but plain weaving is good in view of
uniformity of physical property of a woven fabric. As a yarn, a
wrap and a weft may not be single or not, and may be different, for
example, in a thickness, the number, and a fiber kind of yarns.
[0024] The woven fabric in the present invention can be produced by
coating a synthetic resin on at least one side of a synthetic fiber
woven fabric made by the known method. The coating method is not
particularly limited, but the known method can be used and, in view
of the cost and flexibility of the woven fabric after coating, it
is preferable to use knife coating.
[0025] In the present invention, as a synthetic resin to be coated
on a woven fabric, a polyurethane-based resin, an acryl-based
resin, a polyester-based resin, and a polyamide-based resin can be
used and, among them, a polyamide-based resin having a soft segment
comprising an amino-modified polyol having a number average
molecular weight of 100 to 5000 is preferable from a viewpoint of
air permeability. A more preferable molecular weight of a polyol is
300 to 3000. When a molecular weight is less than 100, since a
tearing strength is reduced, this is not preferable. When a
molecular weight is more than 5000, since a sliding resistance
force is easily deficient, this is not preferable. Measurement of a
number average molecular weight was performed as follows:
--GPC method
Apparatus: TOSOH HLC-8330GPC
Column: TSKgel SuperHM-Hx3 TSKgel SuperH2000 (TOSOH)
[0026] Solvent: HFIP/sodium trifluoroacetate 10 mM Flow rate: 0.25
ml/min Concentration: 0.05% Temperature: 40.degree. C., detector:
RI A molecular weight was calculated in terms of standard
polymethyl methacrylate.
[0027] Herein, the soft segment refers to a whole polyol, and
amino-modified linear polyalkylene glycol is preferable from a
viewpoint of performance of the thermoplastic resin. More
preferable is polyethylene glycol, polypropylene glycol,
polytetramethylene glycol or polybutylene glycol, each being
amino-modified. It is preferable that the polyol is 10 to 90% by
mass in terms of a mass ratio in a polymer. When the ratio is less
than 10% by mass, flexibility of a woven fabric after coating is
lost, being not preferable. When the ratio exceeds 90% by mass, a
nature as an elastomer is not obtained, and air permeability is
increased, being not preferable.
[0028] In the present invention, a melting point of a synthetic
resin to be coated on a woven fabric is in a range of preferably
120 to 180.degree. C., more preferably 125 to 160.degree. C.,
further preferably 130 to 145.degree. C. In a woven fabric for an
airbag in which at least one side is coated with the synthetic
resin, in order to improve heat aging resistance, it is preferable
that a melting point of the synthetic resin is 120.degree. C. or
higher. In addition, in order to improve dispersibility is water of
the synthetic resin, a melting point is preferably 180.degree. C.
or lower, further preferably 150.degree. C. or lower.
[0029] As the synthetic resin, the polyetherdiamine compound of the
general formula (I), the dicarboxylic acid compound of the general
formula (II), and a polyamide forming monomer, that is, a polyether
polyamide copolymer obtained by polymerizing the aminocarboxylic
acid compound of the general formula (III) and/or the lactam
compound of the general formula (IV) are preferable.
[0030] In addition, in the polyether polyaminde copolymer, a ratio
of a soft segment relative to a total amount of the resin is in a
range of preferably 70 to 80% by mass, more preferably 73 to 83% by
mass, further preferably 77 to 81% by mass.
[0031] By using the specified polyether polyamide copolymer, air
permeability can be further reduced even in a coated fabric in
which the same amount of a resin is coated on a woven fabric.
[0032] In the polyether polyamide copolymer resin, such a ratio is
preferable that a terminal amino group, and a terminal carboxylic
acid or carboxyl group contained in the polyetherdianime compound,
the dicarboxylic acid compound, and the polyamide forming monomer
are of approximately equal moles.
[0033] Particularly, when one terminus of the polyamide forming
monomer is an amino group, and the other terminus is carboxylic
acid or a carboxyl group, such a ratio is preferable that the
polyetherdiamine compound and the dicarboxylic acid compound are
such that an amino group of the polyetherdiamine compound and a
carboxyl group of the dicarboxylic acid are of approximately equal
moles.
[0034] Examples of the polyetherdiamine compound of the general
formula (I) include polyoxyethylene, 1,2-polyoxypropylene,
1,3-polyoxypropylene and an amino-modified copolymer of them. In
the general formula (I), R represents plural kinds of alkylene
groups in some cases. And, n is a numerical value of 13 to 26.
[0035] As the polyetherdiamine compound of the general formula (I),
a polyetherdiamine compound of the following general formula (V) is
preferable. As an embodiment of the polyetherdiamine compound of
the following formula (V), JEFFAMINE ED900 ((x+z) is about 6.0 and
y is about 12.5 in the general formula (V)) manufactured by
HUNTSMAN, USA can be used.
##STR00002##
[0036] In the polyetherdiamine compound of the general formula (V),
y is preferably 9.2 to 19.4, more preferably 11.0 to 16.7, further
preferably 12.5 to 14.4. And, (x+z) is preferably 3.8 to 6.0, more
preferably 5.0 to 6.0, further preferably 5.5 to 6.0.
[0037] A number average molecular weight of the polyetherdiamine
compound of the formula (I) is in a range of preferably 700 to
1200, more preferably 800 to 1100, further preferably 900 to
1000.
[0038] As the dicarboxylic acid compound of the general formula
(II), at least one kind dicarboxylic acid selected from aliphatic,
alicyclic and aromatic dicarboxylic acids, or a derivative thereof
can be used.
[0039] In the dicarboxylic acid of the general formula (II),
R.sup.1 is preferably a molecular chain of a hydrocarbon of a
carbon number of 1 to 20, or an alkylene group of a carbon number
of 1 to 20, further preferably a molecular chain of a hydrocarbon
of a carbon number of 1 to 15, or an alkylene group of a carbon
number of 1 to 15, more preferably a molecular chain of a
hydrocarbon of a carbon number of 2 to 12, or an alkylene group of
a carbon number of 2 to 12, particularly preferably a molecular
chain of a hydrocarbon of a carbon number of 4 to 10, or an
alkylene group of a carbon number of 4 to 10.
[0040] Examples of the dicarboxylic acid include aliphatic
dicarboxylic acids such as straight aliphatic dicarboxylic acids
such as oxalic acid, succinic acid, glutaric acid, adipic acid,
pimelic acid, suberic acid, azelaic acid, sebacic acid and
dodecanedioic acid, dimerized aliphatic dicarboxylic acids (dimer
acid) of a c number of 14 to 48 obtained by dimerzing unsaturated
fatty acid obtained by fractional distillation of triglyceride, and
hydrogen adducts (hydrogenated dimer acid) of them, alicyclic
dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, and
aromatic dicarboxylic acids such as terephthalic acid and
isophtalic acid. As dimer acid and hydrogenated dimer acid, trade
name "PRIPOL 1004", "PRIPOL 1006", "PRIPOL 1009" and "PRIPOL 1013"
manufactured by Uniquema can be used.
[0041] Then, the aminocarboxylic acid compound of the general
formula (III) and the lactam compound of the general formula (IV)
will be explained.
[0042] In the aminocarboxylic acid compound of the general formula
(III), R.sup.2 is preferably a molecular chain of a hydrocarbon of
a carbon number of 2 to 20, or an alkaline group of a carbon number
of 2 to 20, further preferably a molecular chain of a hydrocarbon
of a carbon number of 3 to 18, or an alkylene group of a carbon
number of 3 to 18, more preferably a molecular chain of a
hydrocarbon of a carbon number of 4 to 15, or an alkylene group of
a carbon number of 4 to 15, particularly preferably a molecular
chain of a hydrocarbon of a carbon number of 4 to 10, or an
alkylene group of a carbon number of 4 to 10.
[0043] In the lactam compound of the general formula (IV), R.sup.3
is preferably a molecular chain of a hydrocarbon of a carbon number
of 2 to 20, or an alkylene group of a carbon number of 2 to 20,
further preferably a molecular chain of a hydrocarbon of a carbon
number of 3 to 18, or an alkylene group of a carbon number of 3 to
18, more preferably a molecular chain of a hydrocarbon of a carbon
number of 4 to 15, or an alkylene group of a carbon number of 4 to
15, particularly preferably a molecular chain of a hydrocarbon of a
carbon number of 4 to 10, or alkylene group of a carbon number of 4
to 10.
[0044] As the aminocarboxylic acid compound and the lactam
compound, at least one polyamide forming monomer including
aliphatic, alicyclic and/or aromatic monomers, selected from
.omega.-aminocarboxylic acid, lactam, those synthesized from
diamine and dicarboxylic acid, and salts thereof are used.
[0045] In those synthesized from diamine and dicarboxylic acid and
salts thereof, examples of diamine include at least one of a
diamine compound selected from aliphatic diamine, alicyclic diamine
and aromatic diamine, and derivatives thereof, and examples of
dicarboxylic acid include at least one kind of a dicarboxylic
compound selected from aliphatic dicarboxylic acid, alicyclic
dicarboxylic acid, and aromatic dicarboxilic acid, and
derivatives.
[0046] A molar ratio of diamine and dicarboxylic acid
(diamine/dicarboxylic acid) is in a range of preferably 0.9 to 1.1,
further preferably 0.93 to 1.07, more preferably 0.95 to 1.05,
particularly preferably 0.97 to 1.03. When the molar ratio is
outside this range, it becomes difficult to increase a molecular
weight in some cases.
[0047] Examples of the .omega.-aminocarboxylic acid include
aliphatic .omega.-aminocarboxylic acids of a carbon number of 5 to
20, such as 6-aminocaproic acid, 7-aminoheptanoic acid,
8-aminooctanoic acid, 10-aminocapric acid, 11-aminoundecanoic acid,
and 12-aminododecanoic acid.
[0048] Examples of the lactam include aliphatic lactams of a carbon
number of 5 to 20, such as .epsilon.-caprolactam,
.omega.-enantholactam, .omega.-undecalactam, .omega.-dodecalactam,
and 2-pyrrolidone.
[0049] In those synthesized form diamine and dicarboxylic acid, and
salts thereof, examples of the diamine include ethylenediamine,
trimethylenediamine, tetramethylenediamine, hexamethylenediamine,
heptamethylenediamine, octamethylenediamine, nonamethylenediamine,
decamethylenediamine, undecamethylenediamine,
dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine,
2,2,4-trimethylhexamethylenediamine, and
3-methylpentamethylenediamine.
[0050] Examples of the dicarboxylic acid include dicarboxylic acids
such as aliphatic dicarboxylic acids of a carbon number of 2 to 20
such as oxalic acid, succinic acid, adipic acid, pimelic acid,
suberic acid, azelaic acid, sebacic acid and dodecanedioic
acid.
[0051] The polyether polyamide copolymer resin can be produced by
the known condensation reaction.
[0052] In production of the polyether polyamide copolymer resin, if
necessary, phosphoric acid compounds such as phosphoric acid,
pyrophosphoric acid and polyphosphoric acid, phosphinic acid
compounds such as dimethylphosphinic acid, phenylmethylphosphinic
acid, hypohosphorous acid, sodium hypophosphite, and ethyl
hypophosphite, sodium phenyl hypophosphite, and ethyl
phenylhypophosphite, phosphonous acid compounds such as
phenylphosphonous acid, sodium phenylphosphonite, and ethyl
phenylphosphonite, phosphonic acid compounds such as
phenylphosphonic acid, ethylphosphonic acid, sodium
phenylplosphonate, diethyl phenylphosphonite, and sodium
ethylphosphonate, and phosphorous acid compounds such as
phosphorous acid, sodium hydrogen phosphite, sodium phosphite,
triethyl phosphite, triphenyl phosphite, and pyrophosphorous acid
can be added as a catalyst.
[0053] And, in order to impart various functions, additives such as
antioxidants, light stabilizers, ultraviolet absorbing agents,
thickeners, coloring agents, crosslinking agents, degradation
preventing agents, inorganic fillers, heat resisting agents,
antistatic agents, lubricants, slip agents, crystal nucleating
agents, adherability imparting agents, sealability improving
agents, anti-fogging agents, releasing agents, plasticizers,
pigments, dyes, perfumes, flame-retardants, reinforcing agents,
metal inactivating agents, neutralizing agents, antacids,
antibacterial agents, fluorescent brighteners, fillers and the like
may be mixed into the synthetic resins to be adhered to the fabric
for an airbag, in such a range that the objective performance of
the present invention is not affected.
[0054] The antioxidant can capture and degrade a peroxy radical and
hydroperoxide which are a main factor for thermal oxidation
degradation, and can suppress weakening of the resin. Furthermore,
the antioxidant in an additive which exhibits remarkable function
of preventing light degradation when used with the light
stabilizer. As a representative antioxidant, there are a hindered
phenol-based antioxidant, a sulfur-based antioxidant, a
phosphorus-base antioxidant, and an amine-base antioxidant.
[0055] Examples of the hindered phenol-based antioxidant include
3,5-di-t-butyl-4-hydroxytoluene,
n-octadecyl-.beta.-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate,
tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methan-
e,
1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene,
calcium (3,5-di-t-butyl-4-hydroxy-benzyl-monoethyl-phosphate),
triethylene glycol
bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate],
pentaerythrityl-tetrakis[3-(3,5-di-t-butylanilino)-1,3,5-triazine,
3,9-bis[1,1-dimethyl-2-{.beta.-(3-t-butyl-4-hydroxy-5-methylphenyl)propio-
nyloxy}ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane,
bis[3,3-bis(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester,
triphenol, 2,2'-ethylidenebis(4,6-di-t-butylphenol),
N,N'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl]hydrazine,
2,2'-oxamidebis[ethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],
1,1,3-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6(1H,3H,5H)--
trione,
1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,
3,5-di-t-butyl-4-hydroxyhydrocinnamic acid
triesterwith-1,3,5-tris(2-hydroxyethyl)-S-triazine-2,4,6(1H,3H,5H),
N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxyhydrocinnamide),
3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimeth-
ylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane and the like.
[0056] Examples of the sulfur-based antioxidant include
dilauryl-3,3'-thiodipropionic acid ester,
dimyristyl-3,3'-thiodipropionic acid ester,
distearyl-3,3'-thiodipropionic acid ester,
laurylstearyl-3,3'-thiodipropionic acid ester,
dilaurylthiodipropionate, dioctadecyl sulfide,
pentaerythritol-tetra(.beta.-lauryl-thiopropionate) ester and the
like.
[0057] Examples of the phosphorus-based antioxidant include
tris(mixed, mono and dinolylphenyl) phosphite,
tris(2,3-di-t-butylphenyl) phosphite,
4,4'-butylidene-bis(3-methyl-6-t-butylphenyl-di-tridecyl)
phosphite,
1,1,3-tris(2-methyl-4-di-tridecylphosphite-5-t-butylphenyl)butane,
tris(2,4-di-t-butylphenyl)phosphite,
bis(2,4-di-t-butylphenyl)pentaerythritol-di-phosphite,
tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene phosphanite,
bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol-di-phosphite,
tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene-di-phosphonite,
triphenyl phosphite, diphenyldecyl phosphite, tridecyl phosphite,
trioctyl phosphite, tridodecyl phosphite, trioctadecyl phosphite,
trinonylphenyl phosphite, tridodecyltrithio phosphite and the
like.
[0058] Examples of the amine-based antioxidant include amines such
as N,N-diphenylethylenediamine, N,N-diphenylacetamidine,
N,N-diphenylformemidine, N-phenylpiperidine,
dibenzylethylenediamine, triethanolamine, phenothiazine,
N,N'-di-sec-butylp-phenylenediamine,
4,4'-tetramethyl-diaminodiphenylmethane,
P,P'-diocytl-diphenylamine,
N,N'-bis(1,4-dimethyl-pentyl)-p-phenylenediamine,
phenyl-.alpha.-naphthylamine, phenyl-.beta.-naphthylamine,
4,4'-bis(4-.alpha.,.alpha.-dimethylbenzyl)diphenylamine and the
like, derivatives thereof, reaction products of amines and
aldehydes, and reaction products of amines and ketones.
[0059] As the light stabilizer, there are ultraviolet absorbing
agents (OVA) which convert light energy into harmless heat energy,
and hindered amine-based light stabilizers (HALS) which capture
radicals generated by photooxidation.
[0060] Examples of the hindered amine-based light stabilizer
include a polycondensate of dimethyl succinate and
1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperodine,
poly[[6-(1,1,3,3-tetrabutyl)imino-1,3,5-triazine-2,4-diyl]hexamethylene[(-
2,2,6,6-tetramethyl-4-piperidyl)imyl]],
bis(1,2,2,6,6-pentamethyl-4-piperidyl) ester of 2-n-butylmalonic
acid,
tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate,
bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, a polycondensate of
N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and
1,2-dibromoethane,
poly[(N,N-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine)-(4-mo-
nopholino-1,3,5-triazine-2,6-diyl)-bis(3,3,5,5-tetramethylpiperazinone)],
tris(2,2,6,6-tetramethyl-4-piperidyl)-dodecyl-1,2,3,4-butanetetracarboxyl-
ate,
tris(1,2,2,6,6-pentamethyl4-piperidyl)-dodecyl-1,2,3,4-butanetetracar-
boxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate,
1,6,11-tris[{4,6-bis(N-butyl-N-(1,2,2,6,6-pentamethylpiperidin-4-yl)amino-
-1,3,5-triazin-2-yl)amino}undecane,
1-[2-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetromethylpip-
eridine,
8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro[4,5]undeca-
ne-2,4-dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, and a
N,N'-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-penta-
methyl-4-piperidyl)amino]-6-chloro-1,3,5-triazine condensate.
[0061] Examples of the ultraviolet absorbing agent include
benzophenone-based, benzotriazole-based, triazole-based,
nickel-based, and salicyl-based ultraviolet absorbing agents.
Examples of the ultraviolet absorbing agent include
2,2'-dihydroxy-4-methoxybenzophenone,
2-hydroxy-4-n-octoxybenzophenone, p-t-butylphenylsalicylate,
2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxy benzoate,
2-(2'-hydroxy-5'-methylphenyl)benzotriazole,
2-(2'-hydroxy-3',5'-di-t-amyl-phenyl)benzotriazole,
2-[2'-hydroxy-3',5'-bis(.alpha.,.alpha.-dimethylbenzylphenyl)benzotriazol-
e, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole,
2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole,
2,5-bis[5'-t-butylbenzoxazolyl-(2)]-thiophene,
bis(3,5-di-t-butyl-4-hydroxybenzylphosphoric acid monoethyl ester)
nickel salt, a mixture of 2-ethoxy-5-t-butyl-2'-ethyloxalic
acid-bis-anilide; 85-90% and
2-ethoxy-5-t-butyl-2'-ethyl-4'-t-butyloxalic acid-bis-anilide;
10-15%,
2-[2-hydroxy-3,5-bis(.alpha.,.alpha.-dimethylbenzyl)phenyl]-2H-be-
nzotriazole, 2-ethoxy-2'-ethyloxalic acid bisanilide,
2-[2'-hydroxy-5'-methyl-3'-(3'',4'',5'',6''-tetrahydrophthalimido-methyl)-
phenyl]benzotriazole,
bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane,
2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole,
2-hydroxy-4-i-octoxybenzophenone,
2-hydroxy-4-dodecyloxybenzophenone,
2-hydroxy-4-octadecyloxybenzophenone, and phenyl salicylate.
[0062] And, it is preferable to mix a water-soluble thickener into
the synthetic resin. The thickener is not particularly limited as
far as it is water-soluble and has the viscosity increasing effect,
but examples thereof include cellulose derivatives such as
carboxymethylcellulose sodium, xanthan gum, carrageenan, cellulose,
and hydroxyethylcellulose. It is preferable that a ratio of the
thickener is adjusted at 30% by mass or less of an adhesion amount
of the synthetic resin after drying. When the ratio is more than
30% by mass, since a tearing force is reduced, and air permeability
is increased, this is not preferable.
[0063] In the present invention, it is necessary that air
permeability of the fabric coated with the synthetic resin under a
differential pressure of 100 kPa is 0.01 to 1.00 L/cm.sup.2/min.
Since a force of 30 to 50 kPa is exerted at development of a normal
airbag, but since there is further influence by heat due to an
explosive of an inflator, it is suitable to discuss air
permeability under a differential pressure of 100 kPa when the
woven fabric is measured in the standard state. Air permeability is
preferably 0.08 L/cm.sup.2/min or less, most preferably 0.50
L/cm.sup.2/min or less. When air permeability is more than 1.00
L/cm.sup.2/min, the human body initial constraining performance is
inferior, being not preferable. When air permeability is less than
0.01 L/cm.sup.2/min, the initial constraining performance is
satisfied, but a great difference between air permeability of this
range is not seen and, additionally, a demerit in the cost and
flexibility due to increase in a resin amount in order to reduce
air permeability is generated, being not preferable. And, it is
preferable that air permeability in JIS L 1096 is less than 0.1
cc/cm.sup.2/sec in the synthetic fiber woven fabric coated with the
synthetic resin.
[0064] In the present invention, it is necessary that a coated
synthetic resin is not present on a weaving yarn part or, if any,
is present at an extremely small amount, and is selectively present
at a border (a crossing line part where a warp and a weft are
crossed) between weaving yarn parts. Specifically, it is necessary
that a film of a synthetic resin coated on the woven fabric is not
present at an upper part of a single yarn, or present at a
thickness of 2 .mu.m or less on a central cross section of a
weaving yarn part (see FIG. 1 cross section and FIG. 2), and is
present at an upper part of a single yarn at a thickness of 2 to 30
.mu.m on a cross section at a border between weaving yarn parts
(see FIG. 1 cross section and FIG. 3). According to the previous
method, since a large amount of a resin is present also on a single
yarn on a central cross section A of a weaving yarn part, low air
permeability more than necessary is obtained, but there are a
demerit on the cost, and inferiority in flexibility due to increase
in a resin amount. On the other hand, when a resin amount is
reduced, necessary air permeability is not obtained. Then, the
present inventors intensively studied in order to obtain necessary
air permeability at a small resin amount and, as a result, found
that a resin film is selectively present at a border between
weaving yarn parts as described above.
[0065] Such the resin film existence state can be attained by the
previously known method and can be attained, for example, by
arbitrarily adjusting a cover factor of the woven fabric, and a
viscosity and a coating amount of a coating agent to be coated as
described below.
[0066] First, it is necessary that a cover factor of the synthetic
fiber woven fabric is adjusted at 2000 to 2500. When the cover
factor is smaller than 2000, a fiber crossing part becomes large, a
larger amount of a resin is present at this crossing part, and it
becomes difficult for the resin to be present selectively, being
not preferable. When the cover factor is larger than 2500,
flexibility is inferior, being not preferable. The cover factor of
the woven fabric is calculated by the following equation 1.
Cover factor = [ warp density ( number / 2.54 cm ) .times. ( warp
fineness ( dtex ) .times. 0.9 ) ] + [ weft density ( number / 2.54
cm ) .times. ( weft fineness ( dtex ) .times. 0.9 ) ] ( equation 1
) ##EQU00002##
[0067] As a coating agent (aqueous dispersion) to be coated on the
woven fabric, a combination of a synthetic resin and the
water-soluble thickener is preferable. Further, it is preferable to
adjust a viscosity of the coating agent at 5 to 200 dPas (measured
with a B-type viscometer). More preferably, the viscosity is 10 to
150 dPas. When the viscosity is smaller than 5dPas, permeability is
enhanced, the desired resin existence state is not obtained and, as
a result, air permeability is increased, being not preferable. When
the viscosity is larger than 200dPas, the resin is attached to
parts other than a necessary part, being not preferable. Herein,
when a water-soluble thickener having a great molecular weight is
used, since a structural viscosity is increased, reduction in the
viscosity considerably occurs at shear generation at a coating step
and, consequently, since the resin permeates into a foundation
cloth, a thickener having a low molecular weight is preferable. As
the thickener, a 1 mass % aqueous solution having a molecular
weight of 100dPas or lower is preferable. A contact pressure/a
tension at coating may be arbitrarily set so that the
aforementioned resin film existence state is obtained.
[0068] In the present invention, an adhesion amount of the
synthetic resin is preferably 0.1 to 15 g/m.sup.2, more preferably
1.0 to 10 g/m.sup.2, further preferably 1.0 to 8.0 g/m.sup.2 in
terms of a mass after drying. The mass after drying is obtained by
subtracting a value of a mass of the woven fabric before coating
measured according to JIS L1096 8.4.2 from a value of a mass of the
woven fabric for an airbag after coating with the synthetic resin
and drying measured according to JIS L1096 8.4.2. When the mass
after drying is less than 0.1 g/m.sup.2, it becomes difficult to
attain air permeability and, when the mass after drying is more
than 15 g/m.sup.2, flexibility is damaged, and the cost is
increased. In the present invention, the woven fabric before
coating means a woven fabric having finished steps other than
coating of a resin just at a stage before coating of a resin and,
usually, shrinkage treatment by heat treatment, an heat setting
have been applied in many cases.
EXAMPLES
[0069] Then, the present invention will be explained in more detail
by way of Examples. Various assessments in Examples were measured
according to the following methods.
(Viscosity of Aqueous Dispersion)
[0070] A viscosity of an aqueous dispersion was measured using a
viscometer (Viscotester VT-04F) manufactured by Rion Co., Ltd.
(Air Permeability)
[0071] Air permeability under a pressure of 100 kPa was measured
using a high pressure air permeability measuring machine
(manufactured by OEM System).
(Resin Film Existence State)
[0072] A central cross section at a weaving yarn part (cross
section A) and a cross section of a border between weaving yarn
parts (cross section B) in FIG. 1 were photographed with a scanning
electron microscope (SEM) to measure a thickness on a single yarn.
As a thickness of the cross section A and that of the cross section
B, thicknesses in a direction perpendicular with a fiber of a resin
present on single yarn apexes situated at three positions which
divide a multifilament width into four were measured, respectively,
and an average of these thicknesses was taken.
Example 1
[0073] A polyamide 66 fiber of a total fineness of 400 dtex, and 72
filaments was woven in a water jet room in a plain weaving manner,
shrinkage-processed with boiling water, and drying-finished at
110.degree. C. to obtain a woven fabric having a warp density of
58/2.54 cm and a weft density of 56/2.54 cm. Using a polymer
obtained by polymerizing a polyamide 6, a polyethylene
glycol-propylamine adduct (number average molecular weight 600) and
adipic acid at a molar ratio of 2.5:1:1, an aqueous resin
dispersion having a solid matter concentration of 6% by mass was
made. Then, to the aqueous dispersion was added
carboxymethylcellulose sodium (1105, manufactured by Daicel
Chemical Industries, Ltd.) at 10% by mass relative to the aqueous
resin, and a viscosity was adjusted to 25 dPas. An aqueous
dispersion of this resin composition was coated on the woven fabric
by knife coating, at a resin amount after drying of 4 g/cm.sup.2.
Properties of this woven fabric were assessed, and results are
shown in Table 1.
Example 2
[0074] A polyamide 66 fiber of a total fineness of 350 dtex, and
108 filaments was woven in a water jet room in a plain weaving
manner, shrinkage-processed with boiling water, and drying-finished
at 110.degree. C. to obtain a woven fabric having a warp density of
64/2.54 cm and a weft density of 61/2.54 cm. Using a polymer
obtained by polymerizing a polyamide 6, a polypropylene
glycol-propylamine adduct (number average molecular weight 1000)
and adipic acid at a molar ratio of 2.0:1:1, an aqueous resin
dispersion having a solid matter concentration of 10% by mass was
made. Then, to the aqueous dispersion was added
carboxyethylcellulose (SP200, manufactured by Daicel Chemical
Industries, Ltd.) at 8% by mass relative to the aqueous resin, and
a viscosity was adjusted to 20 dPas. An aqueous dispersion of this
resin composition was coated on the woven fabric by knife coating,
at a resin amount after drying of 10 g/cm.sup.2. Properties of this
woven fabric were assessed, and results are shown in Table 1.
Example 3
[0075] A polyamide 66 fiber of a total fineness of 350 dtex, and
108 filaments was woven in a water jet room in a plain weaving
manner, shrinkage-processed with boiling water, and drying-finished
at 110.degree. C. to obtain a woven fabric having a warp density of
64/2.54 cm and a weft density of 61/2.54 cm. Using a polymer
obtained by polymerizing a polyamide 6, adipic acid, and
polyethylene glycol (number average molecular weight 600) at a
molar ratio of 1.8:1:1, an aqueous resin dispersion having a solid
matter concentration of 6% by mass was made. Then, to the aqueous
dispersion was added carboxymethylcellulose (07326-95, manufactured
by Nacalai Tesque) at 2% by mass relative to the aqueous resin, and
a viscosity was adjusted to 105 dPas. An aqueous dispersion of this
resin composition was coated on the woven fabric by knife coating,
at a resin amount after drying of 8 g/cm.sup.2. Properties of this
woven fabric were assessed, and results are shown in Table 1.
Example 4
[0076] A polyamide 66 fiber of a total fineness of 350 dtex, and
108 filaments was woven in a water jet room in a plain weaving
manner, shrinkage-processed with boiling water, and drying-finished
at 110.degree. C. to obtain a woven fabric having a warp density of
64/2.54 cm and a weft density of 61/2.54 cm. Using a polymer
obtained by polymerizing a polyamide 6, a polytetramethylene
glycol-propylamine adduct (number average molecular weight 1000)
and adipic acid at a molar ratio of 2.0:1:1, an aqueous resin
dispersion having a solid matter concentration of 10% by mass was
made. Then, to the aqueous dispersion was added
carboxymethylcellulose (07326-95, manufactured by Nacalai Tesque)
at 1% by mass relative to the aqueous resin, and a viscosity was
adjusted to 15 dPas. An aqueous dispersion of this resin
composition was coated on the woven fabric by knife coating, at a
resin amount after drying of 2 g/cm.sup.2. Properties of this woven
fabric were assessed, and results are shown in Table 1.
Example 5
[0077] A reactor of a volume of about 5 L equipped with a stirrer,
a temperature controller, a manometer, a nitrogen gas inlet, a
condensation water outlet, and a pressure regulator was charged
with 1005.45 g of polyether diamine (JEFFAMINE ED900, manufactured
by HUNTSMAN, total amine: 2.16 meq/g, number average molecular
weight 900), 158.68 g of adipic acid (AA), 375.00 g of
.epsilon.-caprolactam (.epsilon.-CL), and 22.5 mL of an aqueous
phosphoric acid solution (63.2 g/L), the interior of the container
was sufficiently replaced with nitrogen, a temperature was raised
to 230.degree. C. over 0.5 hour, and polymerization was performed
at 230.degree. C. for 4.0 hours. Thereafter, polymerization was
performed for 1.5 hours under reduced pressure, subsequently, a
pressure in the container was reduced with a pressure regulating
device over 1.0 hour while retaining at 230.degree. C. and,
further, polymerization was performed at 230.degree. C. for 0.5
hour to obtain a polymer.
[0078] Using the resulting polymer, an aqueous resin dispersion
having a solid matter concentration of 20% by mass was prepared.
Then, to the aqueous dispersion was added carboxylmethylcellulose
(1105, manufactured by Daicel Chemical Industries, Ltd.) at 5% by
mass relative to the aqueous resin to adjust a viscosity to 25
dPas. An aqueous dispersion of this resin composition was coated on
one side of the woven fabric used in Example 1 by knife coating, to
a resin amount after drying of 4 g/m.sup.2. Properties of this
woven fabric were assessed, and results are shown in Table 1.
Comparative Example 1
[0079] A polyamide 66 fiber of a total fineness of 400 dtex, and
108 filaments was woven into a fabric in a water jet room in a
plain weaving manner, shrinkage-processed with boiling water, and
drying-finished at 110.degree. C. to obtain a woven fabric having a
warp density of 58/2.54 cm and a weft density of 56/2.54 cm. Using
a polymer obtained by polymerizing a polyamide 6, a polyethylene
glycol-propylamine additive (number average molecular weight 600)
and adipic acid at a molar ratio of 2.5:1:1, an aqueous resin
dispersion having a solid matter of 6% by mass was prepared. Then,
to the aqueous dispersion was added carboxymethylcellulose sodium
(1105, manufactured by Daicel Chemical Industries, Ltd.) at 2% by
mass relative to the aqueous resin to adjust a viscosity to 4 dPas.
An aqueous dispersion of this resin composition was coated on the
woven fabric by knife coating, to a resin amount after drying of 6
g/m.sup.2. Properties of this woven fabric were assessed, and
results are shown in Table 1.
Comparative Example 2
[0080] A polyamide 66 filament of a total fineness of 350 dtex, and
108 filaments was woven into a fabric in a water jet room in a
plain weaving manner, and drying-finished at 110.degree. C. to
obtain a woven fabric having a warp density of 63/2.54 cm and a
weft density of 61/2.54 cm. A solvent-free silicone resin
(viscosity: 300 dPas) was coated on this woven fabric, to a resin
amount after drying of 25 g/m.sup.2. Properties of this woven
fabric were assessed, and results are shown in Table 1.
Comparative Example 3
[0081] A polyamide 66 filament of a total fineness of 470 dtex, and
72 filaments was woven into a fabric in a water jet room in a plain
weaving manner, and drying-finished at 110.degree. C. to obtain a
woven fabric having a warp density of 46/2.54 cm and a weft density
of 46/2.54 cm. Using a polymer obtained by polymerizing a polyamide
6, a polyethylene glycol-propylamine additive (number average
molecular weight 600) and adipic acid at a molar ratio of 2.5:1:1,
an aqueous resin dispersion having a solid matter concentration of
6% by mass was made. Then, to the aqueous dispersion was added
carboxymethylcellulose sodium (1105, manufactured by Daicel
Chemical Industries, Ltd.) at 10% by mass relative to the aqueous
resin, and a viscosity was adjusted to 25 dPas. An aqueous
dispersion of this resin composition was coated on the woven fabric
by knife coating, at a resin amount after drying of 4 g/cm.sup.2.
Properties of this woven fabric were assessed, and results are
shown in Table 1.
TABLE-US-00001 TABLE 1 Comparative Example Example Unit 1 2 3 4 5 1
2 3 Total fineness dtex 400 350 350 350 400 400 350 470 Filament
number Number 108 108 108 108 108 108 108 72 Density Warp Number/
58 64 64 64 58 58 64 46 inch Weft Number/ 56 61 61 61 56 56 61 46
inch Cover factor -- 2163 2219 2219 2219 2163 2163 2219 1892 Resin
amount g/m.sup.2 4 10 8 2 4 6 25 4 Air permeability L/cm.sup.2/min
0.78 0.45 0.38 0.35 0.16 2.8 <0.01 4.0 Resin thickness on .mu.m
<1 <1 1 <1 <1 <1 6 <1 cross section A Resin
thickness on .mu.m 6 11 15 3 7 <1 30 <1 cross section B
[0082] In Examples 1 to 5, by bringing about the resin film
existence state of the present invention, low air permeability
could be attained at a small adhesion amount. Particularly, when
Examples 1 and 5 are compared in which only a kind of the resin to
be adhered to the woven fabric is different, it is seen that air
permeability is considerably reduced even at a small adhesion
amount of the resin in Example 5. On the other hand, in Comparative
Examples 1 and 3, low air permeability can not be attained due to
the bad resin film existence state. In addition, in Comparative
Example 2, low air permeability can be attained, but a resin amount
is extremely large, and accommodability and economy are
inferior.
[0083] As apparent from results of Examples 1 to 5, and Comparative
Examples 1 to 3, the present invention can provide a woven fabric
for an airbag which is of the low cost, is excellent in
accommodability, and has air permeability satisfying the human body
initial constraining performance as compared with the previous
woven fabrics for an airbag.
INDUSTRIAL APPLICABILITY
[0084] Since the woven fabric for an airbag of the present
invention is of the low cost, is excellent in accommodability, and
has air permeability satisfying the human body initial constraining
performance, it can be utilized for an airbag which is one of
automobile safety devices, and considerably contributes to the
industrial field.
* * * * *