U.S. patent application number 11/631931 was filed with the patent office on 2008-02-21 for hollow weave fabric for an air bag and method of producing the same.
This patent application is currently assigned to Asahi Kasei Chemicals Corporation. Invention is credited to Toshiro Nagaoka.
Application Number | 20080042414 11/631931 |
Document ID | / |
Family ID | 35785185 |
Filed Date | 2008-02-21 |
United States Patent
Application |
20080042414 |
Kind Code |
A1 |
Nagaoka; Toshiro |
February 21, 2008 |
Hollow Weave Fabric for an Air Bag and Method of Producing the
Same
Abstract
A hollow weave fabric for an air bag in which the periphery of a
double-layer hollow weave portion is formed with a seam zone,
wherein the warp yarn and the weft yarn forming the base fabric are
each a poly(hexamethylene adipamide) fiber having a total size of
150 to 500 dtex, the double-layer hollow weave portion has a fabric
weight of 120 to 350 g/m.sup.2 on one side, and the fabric shows a
logarithmic decrement of 0.01 to 0.10.
Inventors: |
Nagaoka; Toshiro; (Hyogo,
JP) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700
1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
Asahi Kasei Chemicals
Corporation
Tokyo
JP
|
Family ID: |
35785185 |
Appl. No.: |
11/631931 |
Filed: |
July 14, 2005 |
PCT Filed: |
July 14, 2005 |
PCT NO: |
PCT/JP05/13049 |
371 Date: |
January 9, 2007 |
Current U.S.
Class: |
280/743.1 ;
139/188R; 139/383R |
Current CPC
Class: |
B60R 2021/23547
20130101; B60R 21/235 20130101; D03D 1/02 20130101; D06M 15/643
20130101; D06N 3/0002 20130101; B60R 2021/23509 20130101; D06N
3/128 20130101; B60R 21/16 20130101 |
Class at
Publication: |
280/743.1 ;
139/188.00R; 139/383.00R |
International
Class: |
B60R 21/16 20060101
B60R021/16; D03D 1/02 20060101 D03D001/02; D06M 15/643 20060101
D06M015/643 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 16, 2004 |
JP |
2004-210393 |
Claims
1. A hollow weave fabric for an air bag in which the periphery of a
double-layer hollow weave portion is formed with a seam zone,
wherein the warp yarn and the weft yarn forming the base fabric are
each a poly(hexamethylene adipamide) fiber having a total size of
150 to 500 dtex, the double-layer hollow weave portion has a fabric
weight of 120 to 350 g/m2 on one side, and the fabric shows a
logarithmic decrement of 0.01 to 0.10.
2. The hollow weave fabric for an air bag according to claim 1,
wherein the double-layer hollow weave portion has a coating layer
of a silicone composition.
3. The hollow weave fabric for an air bag according to claim 2,
wherein the silicone composition contains an organopolysiloxane
containing a SiC-bonded vinyl group at a terminal end and having a
viscosity of 1,000 to 1,000,000 mPas at 25.degree. C.
4. The hollow weave fabric for an air bag according to claim 3,
wherein the double-layer hollow weave portion has at least two
coating layers each formed of a silicone composition, and the
following (1) and (2) are satisfied: (1) a first layer is a coating
on the surface of the woven fabric, and the coating amount of the
silicone composition is from 3 to 30 g/m2 as a solid component; and
(2) a second layer is formed on the surface of the first layer, and
the coating amount of the silicone composition is from 20 to 90
g/m2 as a solid component.
5. The hollow weave fabric for an air bag according to claim 4,
wherein the first silicone coating layer is formed of a silicone
composition containing 0.1 to 4.5% by weight of a coupling agent
comprising an organosilicon compound.
6. The hollow weave fabric for an air bag according to claim 4,
wherein the tensile elongation of the silicone composition after
curing in the first silicone coating layer is 350% or less.
7. The hollow weave fabric for an air bag according to claim 4,
wherein the first silicone coating layer is formed of a silicone
composition containing an organopolysiloxane that contains a
SiC-bonded vinyl group at a terminal end and that has a viscosity
of 1,000 to 100,000 mPas at 25.degree. C.
8. The hollow weave fabric for an air bag according to claim 4,
wherein the second silicone coating layer is formed of a silicone
composition containing an organopolysiloxane that contains a
SiC-bonded vinyl group at a terminal end and that has a viscosity
of 50,000 to 1,000,000 mPas at 25.degree. C.
9. The hollow weave fabric for an air bag according to claim 4
wherein the coating amount of the silicone composition in the
second silicone coating layer is from 30 to 60 g/m2.
10. The hollow weave fabric for an air bag according to claim 4,
wherein the tensile elongation of the silicone composition after
curing in the second silicone coating layer is 400% or more.
11. The hollow weave fabric for an air bag according to claim 2,
wherein the phase image in the tapping measurement with an SPM at a
cross section of the silicone coating layer is at least two layers
with respect to the woven fabric surface.
12. The hollow weave fabric for an air bag according to claim 11,
wherein the average phase .delta. in the tapping measurement with
an SPM at a cross section of each layer in the first silicone
coating layer and the second one from the woven fabric surface is
as follows: (.delta. of first layer)>(.delta. of second
layer).
13. The hollow weave fabric for an air bag according to claim 11,
wherein the ratio of an average phase .delta. of the first silicone
coating layer from the woven fabric to an average phase .delta. of
the second one therefrom, in the tapping measurements with an SPM
at a cross section of each layer, is from 1.1 to 2.5.
14. The hollow weave fabric for an air bag according to claim 11,
wherein the ratio of an average film thickness D of the first
silicone coating layer from the woven fabric surface to an average
film thickness D of the second one therefrom is as follows:
1/30<[(D of first layer)/(D of second layer)]<1.
15. The hollow weave fabric for an air bag according to claim 1,
wherein the fabric has a layer as a third layer formed by coating
the surface of the second silicone coating layer with a silicone
composition containing 30% by weight or more of an inorganic filler
in an amount of 1 to 25 g/m2 as a solid component.
16. The hollow weave fabric for an air bag according to claim 1,
wherein the fabric is capable of being subjected to a scrub test at
least 500 times after wet heat aging and cooling-heating cycle
aging.
17. A curtain-like air bag formed out of the hollow weave fabric
for an air bag according to claim 1, and capable of retaining a gas
under pressure for a given time.
18. A method of producing a hollow weave fabric for an air bag
composed of a poly(hexamethylene adipamide) fiber of 150 to 500
dtex, and showing a logarithmic decrement of 0.01 to 0.10 at
20.degree. C., the method comprising the steps of applying the
following silicone compositions (1) and (2) as a first coating
layer and a second one, respectively: (1) the silicone composition
for the first coating layer with which the woven fabric surface is
coated contains at least the following elements (a) to (d), and the
silicone composition forming the silicone coating layer shows a
tensile elongation of 350% or less after curing: (a) an
organopolysiloxane containing a SiC-bonded vinyl group at a
terminal unit and having a viscosity of 1,000 to 100,000 mPas at
25.degree. C.; (b) an organopolysiloxane containing at least 3
Si-bonded hydrogen atoms; (c) a catalyst for promoting addition of
a Si-bonded hydrogen atom to aliphatic multiple bonds; and (d) a
coupling agent composed of an organosilicon compound (2) the
silicone composition for the second coating layer with which the
first coating layer surface is coated contains at least the
following (A) to (C), and the silicone composition forming the
silicone coating layer shows a tensile elongation of 400% or more
after curing: (A) an organopolysiloxane containing a SiC-bonded
vinyl group at a terminal unit and having a viscosity of 50,000 to
1,000,000 mPas at 25.degree. C.; (B) an organopolysiloxane
containing at least 3 Si-bonded hydrogen atoms; and (C) a catalyst
for promoting addition of a Si-bonded hydrogen atom to aliphatic
multiple bonds.
19. The method of producing a hollow weave fabric for an air bag
according to claim 18, wherein the weave density of the
double-layer weave portion of the hollow weave fabric is from 40 to
100/2.54 cm.
20. The method of producing a hollow weave fabric for an air bag
according to claim 18, wherein the silicone composition contains
from 0.1 to 4.5% by weight of a coupling agent.
21. The method of producing a hollow weave fabric for an air bag
according to claim 18, wherein the silicone composition is applied,
as the first silicone coating layer, in an amount of 3 to 30 g/m2
as a solid component by a floating knife, a roll-on-knife, gravure
coating or dipping, and the applied silicone composition is heat
treated at 120 to 200.degree. C. for 10 to 600 sec.
22. The method of producing a hollow weave fabric for an air bag
according to claim 18, wherein the silicone composition is applied,
as the second silicone coating layer, in an amount of 20 to 90 g/m2
as a solid component by a floating knife, a roll-on-knife or a
comma coater, and the applied silicone composition is heat treated
at 120 to 200.degree. C. for 10 to 600 sec.
23. The method of producing a hollow weave fabric for an air bag
according to claim 18, wherein the surface of the second silicone
coating layer is coated, as a third layer, with a silicone
composition containing 30% by weight or more of an inorganic
filler, in an amount of 1 to 20 g/m2 as a solid component.
24. The method of producing a hollow weave fabric for an air bag
according to claim 20, wherein the silicone composition contains
0.1 to 3% by weight of a coupling agent.
25. The method of producing a hollow weave fabric for an air bag
according to claim 22, wherein the silicone composition is applied,
as the second silicone coating layer, in an amount of 30 to 60 g/m2
as a solid component.
26. The hollow weave fabric for an air bag according to claim 5,
wherein the tensile elongation of the silicone composition after
curing in the first silicone coating layer is 350% or less.
27. The hollow weave fabric for an air bag according claim 26,
wherein the first silicone coating layer is formed of a silicone
composition containing an organopolysiloxane that contains a
SiC-bonded vinyl group at a terminal end and that has a viscosity
of 1,000 to 100,000 mPas at 25.degree. C.
28. The hollow weave fabric for an air bag according to claim 27,
wherein the second silicone coating layer is formed of a silicone
composition containing an organopolysiloxane that contains a
SiC-bonded vinyl group at a terminal end and that has a viscosity
of 50,000 to 1,000,000 mPas at 25.degree. C.
29. The hollow weave fabric for an air bag according to claim 28
wherein the coating amount of the silicone composition in the
second silicone coating layer is from 30 to 60 g/m2.
30. The hollow weave fabric for an air bag according to claim 29,
wherein the tensile elongation of the silicone composition after
curing in the second silicone coating layer is 400% or more.
31. The hollow weave fabric for an air bag according to claim 30,
wherein the phase image in the tapping measurement with an SPM at a
cross section of the silicone coating layer is at least two layers
with respect to the woven fabric surface.
32. The hollow weave fabric for an air bag according to claim 31,
wherein the average phase .delta. in the tapping measurement with
an SPM at a cross section of each layer in the first silicone
coating layer and the second one from the woven fabric surface is
as follows: (.delta. of first layer)>(.delta. of second
layer).
33. The hollow weave fabric for an air bag according to claim 32
wherein the ratio of an average phase .delta. of the first silicone
coating layer from the woven fabric to an average phase .delta. of
the second one therefrom, in the tapping measurements with an SPM
at a cross section of each layer, is from 1.1 to 2.5.
34. The hollow weave fabric for an air bag according to claim 33,
wherein the ratio of an average film thickness D of the first
silicone coating layer from the woven fabric surface to an average
film thickness D of the second one therefrom is as follows:
1/30<[(D of first layer)/(D of second layer)]<1.
35. The hollow weave fabric for an air bag according to claim 34,
wherein the fabric has a layer as a third layer formed by coating
the surface of the second silicone coating layer with a silicone
composition containing 30% by weight or more of an inorganic filler
in an amount of 1 to 25 g/m2 as a solid component.
36. The hollow weave fabric for an air bag according to claim 35,
wherein the fabric is capable of being subjected to a scrub test at
least 500 times after wet heat aging and cooling-heating cycle
aging.
37. A curtain-like air bag formed out of the hollow weave fabric
for an air bag according to claim 36, and capable of retaining a
gas under pressure for a given time.
38. The method of producing a hollow weave fabric for an air bag
according to claim 20, wherein the silicone composition is applied,
as the first silicone coating layer, in an amount of 3 to 30 g/m2
as a solid component by a floating knife, a roll-on-knife, gravure
coating or dipping, and the applied silicone composition is heat
treated at 120 to 200.degree. C. for 10 to 600 sec.
39. The method of producing a hollow weave fabric for an air bag
according to claim 38, wherein the silicone composition is applied,
as the second silicone coating layer, in an amount of 20 to 90 g/m2
as a solid component by a floating knife, a roll-on-knife or a
comma coater, and the applied silicone composition is heat treated
at 120 to 200.degree. C. for 10 to 600 sec.
40. The method of producing a hollow weave fabric for an air bag
according to claim 39, wherein the surface of the second silicone
coating layer is coated, as a third layer, with a silicone
composition containing 30% by weight or more of an inorganic
filler, in an amount of 1 to 20 g/m2 as a solid component.
41. The method of producing a hollow weave fabric for an air bag
according to claim 39, wherein the silicone composition is applied,
as the second silicone coating layer, in an amount of 30 to 60 g/m2
as a solid component.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a base fabric used for an
air bag that is one of the safety devices of vehicles such as
automobiles. In particular, the present invention relates to a
hollow weave fabric for an air bag for protecting an occupant of a
vehicle during collision, and a method of producing the same.
BACKGROUND ART
[0002] Improvement of the safety of occupants in vehicles such as
automobiles has been required in recent years, and the installation
ratio of air bags has been improved. An air bag is a module wherein
a sensor detects the impact a vehicle encounters during a head-on
collision, a rear-end collision or a side collision of the vehicle,
a gas is then blown into an expandable bag portion from an inflator
to rapidly deploy and expand the air bag, and the cushioning of the
air bag protects the occupant.
[0003] Conventional air bags are often installed in the front
portion of a driver's seat and an assistant driver's seat,
respectively, and are often installed to protect the faces and the
upper half parts of the bodies of occupants principally during a
head-on collision. A curtain-like air bag capable of corresponding
to a side collision and a sideway rolling (hereinafter referred to
as rollover) has recently been developed.
[0004] The curtain-like air bag is stored in, for example, a region
from the front pillar side to the rear pillar side along the roof
rail of the sidewall within an automobile, and designed to be
expanded and deployed along the side windows during a collision.
Moreover, for the curtain-like air bag, an expandable bag-like
portion is formed at each of the plurality of sites, and the air
bag is long and large and has a complicated shape. The curtain-like
air bag is required to be excellent in storability (compactness).
Furthermore, because the distance between the head portion of an
occupant and the side glass window is short, the air bag must
instantaneously enter between the occupant's head portion and the
window glass to protect the head portion during a side collision.
That is, the air bag is required to have a rapid deployment speed.
Furthermore, correspondence of the air bag to a rollover accident
in which the automobile side rolls several times is taken into
consideration, and it is required that the internal pressure of the
air bag not lower too much for a certain period. That is, the air
bag is required to retain the internal pressure of 40 kPa or more
for about 8 sec after expansion and deployment.
[0005] Furthermore, the internal pressure retention performance of
the air bag is originally expected to function even after the air
bag is exposed to a variety of environments. However, the air bag
has actually not displayed the internal pressure retaining function
under severe environmental test conditions such as heat aging, wet
heat aging and cooling-heating cycle aging.
[0006] When the coating film thickness is increased in order to
enhance the internal pressure retention performance, the air bag
weight is undesirably increased. Moreover, the air bag cannot pass
a severe environment test. In order to further increase the
deployment speed, the woven fabric forming the base fabric must be
made light weight.
[0007] There is one type of curtain-like air bag that is prepared
by cutting a plurality of cloths, and sewing the cut cloths. In
order to prevent air leakage caused by a sewing needle, the seams
of the air bag are filled with a sealing agent, and the sites are
sewn with a thick sewing thread for the purpose of ensuring burst
resistance. As a result, the air bag has the following problems:
the air bag has poor storability; and sewing the air bag takes a
lot of time.
[0008] Japanese Unexamined Patent Publication (Kokai) No. 3-16852
discloses preparation of a bag-like high density woven fabric in
which the periphery of the hollow weave portion is closed with a
single-layer portion, and use of it as an air bag. However, such a
woven fabric is formed out of a synthetic warp yarn and a synthetic
weft yarn each having a total size of 500 dtex or more. It has a
large amount of coating for the purpose of preventing air leakage,
and a fabric weight of 700 g/m.sup.2. The air bag does therefore
not sufficiently satisfy the requirement of light weight.
[0009] Japanese Unexamined Patent Publication (Kokai) No. 11-1876
discloses a fiber woven fabric having two coating layers. The first
layer is formed by coating with a high elongation silicone, and the
second layer is formed by coating with a high tear strength
silicone. When the base fabric is coated with a high elongation
silicone as the first layer, the air bag before aging shows good
internal pressure retention. However, the high elongation silicone
has poor adhesion to the woven fabric and the following problems
result: the internal pressure retention after aging deteriorates
after wet heat aging and cooling-heating cycle aging; and
delamination of the silicone film sometimes takes place.
[0010] Japanese Patent Publication No. 2003-526557 discloses a
technology of coating with a mixture of a silicone compound and a
non-silicone compound as a first layer and a silicone compound as a
second layer. The patent publication describes that the coating
amount can be made small according to the technology, and that the
internal pressure retention of the air bag can be maintained even
after heat aging and wet heat aging. However, in conventional air
bags, the adhesive strength of the first coating layer
significantly lowers in the cooling region during cooling-heating
cycle aging, and the air bag cannot withstand the initial pressure
during expansion and deployment; as a result, the air bag cannot
maintain the internal pressure retaining function.
[0011] Japanese Unexamined Patent Publication (Kokai) No.
2003-327910 discloses a silicone composition the silicone coating
layer of which is not delaminated during deployment of an air bag
and is excellent in internal pressure retention. However, there is
no disclosure in the above patent specification regarding internal
pressure retention during air bag deployment after aging.
DISCLOSURE OF THE INVENTION
Problems to Be Solved by the Invention
[0012] In view of the conventional technologies as explained above,
an object of the present invention is to provide a hollow weave
fabric for an air bag excellent in internal pressure retention
during air bag deployment after wet heat aging and cooling-heating
cycle aging, and to provide a hollow weave fabric suitable for a
curtain-like air bag that is made light weight.
Means for Solving the Problems
[0013] As a result of extensive investigations, the present
inventors have found that the above problems can be solved by
specifying the total size of a warp yarn and that of a weft yarn
forming the base fabric in a hollow weave fabric for an air bag in
which the periphery of the double-layer hollow weave portion is
formed with a seam zone, and employing a coating composition
showing a high logarithmic decrement. According to the present
invention, a curtain-like air bag excellent in internal pressure
retention before and after aging in comparison with conventional
ones, and being made light weight can be obtained.
[0014] The present invention is as explained below.
[0015] 1) A hollow weave fabric for an air bag in which the
periphery of a double-layer hollow weave portion is formed with a
seam zone, wherein the warp yarn and the weft yarn forming the base
fabric are each a poly(hexamethylene adipamide) fiber having a
total size of 150 to 500 dtex, the double-layer hollow weave
portion has a fabric weight of 120 to 350 g/m.sup.2 on one side,
and the fabric shows a logarithmic decrement of 0.01 to 0.10.
[0016] 2) The hollow weave fabric for an air bag according to 1
described above, wherein the double-layer hollow weave portion has
a coating layer of a silicone composition.
[0017] 3) The hollow weave fabric for an air bag according to 2
describes above, wherein the silicone composition contains an
organopolysiloxane containing a SiC-bonded vinyl group at a
terminal end and having a viscosity of 1,000 to 1,000,000 mPas at
25.degree. C.
[0018] 4) The hollow weave fabric for an air bag according to 3
described above, wherein the double-layer hollow weave portion has
at least two coating layers each formed of a silicone composition,
and the following conditions (1) and (2) are satisfied:
[0019] (1) a first layer is a coating on the surface of the woven
fabric, and the coating amount of the silicone composition is from
3 to 30 g/m.sup.2 as a solid component; and
[0020] (2) a second layer is formed on the surface of the first
layer, and the coating amount of the silicone composition is from
20 to 90 g/m.sup.2 as a solid component.
[0021] 5) The hollow weave fabric for an air bag according to 4
described above, wherein the first silicone coating layer is formed
of a silicone composition containing 0.1 to 4.5% by weight of a
coupling agent comprising an organosilicon compound.
[0022] 6) The hollow weave fabric for an air bag according to 4 or
5 described above, wherein the tensile elongation of the silicone
composition after curing in the first silicone coating layer is
350% or less.
[0023] 7) The hollow weave fabric for an air bag according to any
of 4 to 6 described above, wherein the first silicone coating layer
is formed of a silicone composition containing an
organopolysiloxane that contains a SiC-bonded vinyl group at a
terminal end and that has a viscosity of 1,000 to 100,000 mPas at
25.degree. C.
[0024] 8) The hollow weave fabric for an air bag according to any
of 4 to 7 described above, wherein the second silicone coating
layer is formed of a silicone composition containing an
organopolysiloxane that contains a SiC-bonded vinyl group at a
terminal end and that has a viscosity of 50,000 to 1,000,000 mPas
at 25.degree. C.
[0025] 9) The hollow weave fabric for an air bag according to any
of 4 to 8 described above, wherein the coating amount of the
silicone composition in the second silicone coating layer is from
30 to 60 g/m.sup.2.
[0026] 10) The hollow weave fabric for an air bag according to any
of 4 to 9 described above, wherein the tensile elongation of the
silicone composition after curing in the second silicone coating
layer is 400% or more.
[0027] 11) The hollow weave fabric for an air bag according to any
of conditions 2 to 10 described above, wherein the phase image in
the tapping measurement with an SPM at a cross section of the
silicone coating layer is at least two layers with respect to the
woven fabric surface.
[0028] 12) The hollow weave fabric for an air bag according to
condition 11 described above, wherein the average phase .delta. in
the tapping measurement with an SPM at a cross section of each
layer in the first silicone coating layer and the second one from
the woven fabric surface is as follows: (.delta. of first
layer)>(.delta. of second layer).
[0029] 13) The hollow weave fabric for an air bag according to
condition 11 or 12 described above, wherein the ratio of an average
phase .delta. of the first silicone coating layer from the woven
fabric to an average phase .delta. of the second one therefrom, in
the tapping measurements with an SPM at a cross section of each
layer, is from 1.1 to 2.5.
[0030] 14) The hollow weave fabric for an air bag according to
condition 11 described above, wherein the ratio of an average film
thickness D of the first silicone coating layer from the woven
fabric surface to an average film thickness D of the second one
therefrom is as follows: 1/30<[(D of first layer)/(D of second
layer)]<1.
[0031] 15) The hollow weave fabric for an air bag according to any
of conditions 1 to 14 described above, wherein the fabric has a
layer as a third layer formed by coating the surface of the second
silicone coating layer with a silicone composition containing 30%
by weight or more of an inorganic filler in an amount of 1 to 25
g/m.sup.2 as a solid component.
[0032] 16) The hollow weave fabric for an air bag according to any
of conditions 1 to 15 described above, wherein the fabric is
capable of being subjected to a scrub test at least 500 times after
wet heat aging and cooling-heating cycle aging.
[0033] 17) A curtain-like air bag formed out of the hollow weave
fabric for an air bag according to any of conditions 1 to 16
described above, and capable of retaining a gas under pressure for
a given time.
[0034] 18) A method of producing a hollow weave fabric for an air
bag composed of a poly(hexamethylene adipamide) fiber of 150 to 500
dtex, and showing a logarithmic decrement of 0.01 to 0.10 at
20.degree. C., the method comprising the steps of applying the
following silicone compositions (1) and (2) as a first coating
layer and a second one, respectively:
[0035] (1) the silicone composition for the first coating layer
with which the woven fabric surface is coated contains at least the
following (a) to (d), and the silicone composition forming the
silicone coating layer shows a tensile elongation of 350% or less
after curing:
[0036] (a) an organopolysiloxane containing a SiC-bonded vinyl
group at a terminal unit and having a viscosity of 1,000 to 100,000
mPas at 25.degree. C.;
[0037] (b) an organopolysiloxane containing at least 3 Si-bonded
hydrogen atoms;
[0038] (c) a catalyst for promoting addition of a Si-bonded
hydrogen atom to aliphatic multiple bonds; and
[0039] (d) a coupling agent composed of an organosilicon
compound;
[0040] (2) the silicone composition for the second coating layer
with which the first coating layer surface is coated contains at
least the following elements (A) to (C), and the silicone
composition forming the silicone coating layer shows a tensile
elongation of 400% or more after curing:
[0041] (A) an organopolysiloxane containing a SiC-bonded vinyl
group at a terminal unit and having a viscosity of 50,000 to
1,000,000 mPas at 25.degree. C.;
[0042] (B) an organopolysiloxane containing at least 3 Si-bonded
hydrogen atoms; and
[0043] (C) a catalyst for promoting addition of a Si-bonded
hydrogen atom to aliphatic multiple bonds.
[0044] 19) The method of producing a hollow weave fabric for an air
bag according to condition 18 described above, wherein the weave
density of the double-layer weave portion of the hollow weave
fabric is from 40 to 100/2.54 cm.
[0045] 20) The method of producing a hollow weave fabric for an air
bag according to condition 18 or 19 described above, wherein the
silicone composition contains from 0.1 to 4.5% by weight of a
coupling agent.
[0046] 21) The method of producing a hollow weave fabric for an air
bag according to any of conditions 18 to 20 described above,
wherein the silicone composition is applied, as the first silicone
coating layer, in an amount of 3 to 30 g/m.sup.2 as a solid
component by a floating knife, a roll-on-knife, gravure coating or
dipping, and the applied silicone composition is heat treated at
120 to 200.degree. C. for 10 to 600 sec.
[0047] 22) The method of producing a hollow weave fabric for an air
bag according to any of conditions 18 to 21 described above,
wherein the silicone composition is applied, as the second silicone
coating layer, in an amount of 20 to 90 g/m.sup.2 as a solid
component by a floating knife, a roll-on-knife or a comma coater,
and the applied silicone composition is heat treated at 120 to
200.degree. C. for 10 to 600 sec.
[0048] 23) The method of producing a hollow weave fabric for an air
bag according to any of conditions 18 to 22 described above,
wherein the surface of the second silicone coating layer is coated,
as a third layer, with a silicone composition containing 30% by
weight or more of an inorganic filler, in an amount of 1 to 20
g/m.sup.2 as a solid component.
[0049] 24) The method of producing a hollow weave fabric for an air
bag according to condition 20 described above, wherein the silicone
composition contains 0.1 to 3% by weight of a coupling agent.
[0050] 25) The method of producing a hollow weave fabric for an air
bag according to condition 22 described above, wherein the silicone
composition is applied, as the second silicone coating layer, in an
amount of 30 to 60 g/m.sup.2 as a solid component.
[0051] The present invention will now be explained in detail
below.
[0052] A poly(hexamethylene adipamide) (hereinafter merely referred
to as nylon 66) fiber or a fiber mainly containing
poly(hexamethylene adipamide) is preferably used as a warp yarn and
a weft yarn that form the hollow weave fabric for an air bag of the
invention. In particular, in view of heat resistance, a nylon 66
fiber, a nylon 66 copolymer (such as nylon 66/6, nylon 66/61 and
nylon 66/610) fiber and a nylon 66 fiber in which a nylon polymer
such as a nylon 6 or a nylon 610 is blended, having a melting point
of 215.degree. C. or more is preferred.
[0053] In the present invention, a nylon 66 fiber can be produced
by a known spinning and drawing method or a known spinning and
direct drawing method.
[0054] In order to improve the processability of such fiber yarns
in the raw yarn production step and after-processing step, the
fiber yarns may be made to contain various additives. For example,
one or at least two materials selected from heat stabilizers, light
stabilizers, aging retarders, antioxidants, lubricants, smooth
finishing agents, pigments, water-repellents, oil-repellents,
masking agents such as titanium oxide, lustering agents, fire
retardants, plasticizers, antistatic agents, thickeners, and the
like. Moreover, if necessary, the yarns can be texturized forms
such as twisted yarns, bulked yarns, crimped yarns and wound
yarns.
[0055] Furthermore, in order to improve the cohesiveness and
drawability of the fiber during spinning, a known finishing agent
for spinning may be applied to the fiber in an amount of 0.1 to 5%
by weight.
[0056] The total size of a warp yarn and a weft yarn forming the
hollow weave fabric for an air bag must be from 150 to 500 dtex,
preferably from 150 to 350 dtex. When the total size is in the
above range, the hollow weave fabric can withstand the tenacity
during deployment inflation. The base fabric becomes flexible at
the same time to improve the storability of the air bag, and the
air bag can be deployed at high speed. When a warp yarn and a weft
yarn each having a total size in the above range are used, the
fabric weight in the hollow weave portion becomes from 90 to 280
g/m.sup.2.
[0057] When the total size is less than 150 dtex, the mechanical
strength of the air bag becomes insufficient during deployment, and
a burst phenomenon sometimes takes place. Moreover, when the total
size exceeds 500 dtex, the thickness of the base fabric increases,
and the storability of the air bag becomes poor due to a decrease
in the foldability thereof. Furthermore, because the base fabric
weight increases, the deployment speed becomes slow.
[0058] Furthermore, the single filament size of a warp yarn and a
weft yarn is from 0.1 to 7 dtex, preferably from 0.5 to 5.0 dtex.
There is no specific limitation on the single filament
cross-sectional shape of a warp yarn and a weft yarn. For example,
a round shape or a shape-modified cross section such as a
triangular shape or a flat shape is employed. In order to for the
yarns to have maximum strength, a round shape cross section is
preferred.
[0059] Furthermore, the tensile strength of a yarn forming the base
fabric is preferably 5.7 cN/dtex or more, more preferably 6.2
cN/dtex or more. When the tensile strength is 5.7 cN/dtex or more,
the air bag thus obtained can satisfy the pressure resistance
tenacity required during deployment. A particularly preferred
tensile strength is from 6.2 to 11 cN/dtex.
[0060] For the woven fabric used for the hollow weave fabric for an
air bag of the present invention, the upper cloth and the lower
cloth of the double-layer hollow weave portion that is expanded
when a fluid is introduced thereinto are preferably formed out of a
plain structure. The fabric weight of one side of the double-layer
hollow weave portion is from 120 to 350 g/m.sup.2. Moreover, it is
further preferred that the periphery of the double-layer hollow
weave portion be formed out of a seam zone that is formed out of a
reversible figured weave and a basket weave pattern. The base unit
of the basket weave pattern is formed out of warp yarns and weft
yarns crossing each other in the sinking/floating direction. The
basket weave pattern is a structure in which the base unit is
repeated both in the longitudinal and lateral directions. The
basket weave pattern is sometimes referred to as a mat structure, a
basket structure, or the like structure.
[0061] In the present invention, the logarithmic decrement is a
value measured with a rigid pendulum type physical property tester
(trade name of RPT-3000, manufactured by A and D Co., Ltd.). In
order for a light weight coating resin of the air bag to absorb the
impact during deployment of the air bag, the logarithmic decrement
of the coated fabric at 20.degree. C. must be from 0.01 to 0.10,
preferably from 0.02 to 0.06. When the logarithmic decrement is
less than 0.01, the resin shows no impact absorption, and air
leakage may take place during deployment of the air bag. Moreover,
when the logarithmic decrement of the resin is larger than 0.10,
the air bag has too soft a surface, and tucking properties are
produced. As a result, the operationability of folding the air bag
becomes poor, and the deployment of the air bag also becomes
poor.
[0062] In the present evaluation, a blade is first placed on a
sample surface, and the blade sinks due to its weight. As a result,
both sides of the blade are in contact with the sample. The blade
is then vibrated as a pendulum. The blade presses the vibration
amplitude of the sample back on the surface of the blade contacted
with the sample. The behavior of the blade produces a free
decrement. In the present evaluation, the manner of a free
decrement is measured.
[0063] In the present evaluation, for a sample that is softer and
that as a result shows a larger energy loss when deformed, a higher
decrement is measured. Accordingly, measurements of the coating
surface of an air bag base fabric sample can express the degree of
energy loss caused by the softness and deformation of the coating
layer.
[0064] There is no specific limitation on the coating resin used in
the present invention. A coating resin that is usually used can be
used therein. For example, chloroprene, chlorosulfonated olefin,
silicone rubber, polyamide elastomer, poly(styrene butadiene),
nitrile rubber, fluoro rubber, polyurethane, and the like, can be
employed. Of these materials, a silicone composition having heat
resistance, cold resistance and flame retardancy is preferred.
[0065] The silicone composition used in the present invention
preferably contains a diorganopolysiloxane having a SiC-bonded
vinyl group at a terminal unit. Such a diorganopolysiloxane is
represented by the following general formula:
(CH.sub.2.dbd.CH).sub.xSiR.sub.(3-x)--O(SiR.sub.2O).sub.n--SiR.sub.(3-x)(-
CH.dbd.CH.sub.2).sub.x wherein R represents hydrocarbon groups
preferably having 1 to 18 carbon atoms, R may be substituted with
other atoms or functional groups, R may be of the same hydrocarbon
groups or a mixture of different ones, x is 1, 2 or 3, preferably
1, and n is a numerical value necessary for the
diorganopolysiloxane to have an average viscosity of 1,000 to
1,000,000 mPas at 25.degree. C.
[0066] In order to make the logarithmic decrement 0.01 or more in
the present invention, it is preferred that the organopolysiloxane
mainly used as a composition component for forming a silicone
coating layer have a viscosity of 1,000 mPas or more at 25.degree.
C. When the viscosity is less than 1,000 mPas, a silicone network
structure increases after curing, and a coating film capable of
absorbing an impact during deployment of the air bag cannot be
obtained. Moreover, when the organopolysiloxane has a viscosity
exceeding 1,000,000 mPas at 25.degree. C., the logarithmic
decrement exceeds 0.10. As a result, tucking properties are
produced on the woven fabric surface, and the air bag sometimes
shows poor deployment.
[0067] Preferred examples of the hydrocarbon group R include an
alkyl group such as a methyl group, an ethyl group, an n-propyl
group, an isopropyl group, a butyl group, an octyl group, a
tetradecyl group or an octadecyl group, an alicyclic hydrocarbon
group such as a cyclopentyl group, a cyclohexyl group or a
methylcyclohexyl group, an aryl group such as a phenyl group, an
alkaryl group such as a tolyl group and an aralkyl group such as a
benzyl group or a phenylethyl group.
[0068] Preferred examples of the substituted hydrocarbon group
include a halogenated group such as a 3,3,3-trifluoropropyl group,
a 3-choropropyl group or a chlorophenyl group. A cyanoalkyl group
such as a cyanoethyl group may also be included. A group having an
unsaturated aliphatic group such as a vinyl group, an allyl group,
a hexenyl group or a cyclohexenyl group may also be included.
[0069] The hydrocarbon groups R are preferably ones each having 1
to 10 carbon atoms, more preferably at least 80% of the organic
groups represented as R are methyl groups.
[0070] The above organopolysiloxane may be a group of the same
copolymers. It may also be a mixture of different copolymers each
having a polymerization degree equal to or different from the
others. When the diorganopolysiloxane has diorganopolysiloxane
units different from each other, the units may be randomly
distributed or they may be distributed in blocks.
[0071] In the present invention, the coating film composed of a
silicone composition is preferably composed of two coating layers.
That is, a woven fabric surface is coated with a silicone
composition as a first layer, and the first layer is coated with a
silicone composition as a second layer.
[0072] The coating amount of the silicone composition in the first
layer is preferably from 3 to 30 g/m.sup.2. The composition is used
for coating in order to maintain adhesion to the woven fabric
before and after aging. The amount should preferably be as small as
possible, as long as the bonding function of the coating is
satisfactory, because restriction of the amount contributes to
making the air bag light weight.
[0073] The silicone composition in the second layer is used for
maintaining the silicone film elongation before and after aging,
and contributes to maintaining an internal pressure retention
during deployment of the air bag. The coating amount is preferably
from 20 to 90 g/m.sup.2, more preferably from 30 to 60 g/m.sup.2.
When the coating amount is in the above range, no air leakage takes
place because no broken portion is produced in the coating film
during deployment of the air bag. Moreover, because the hollow
weave fabric has a suitable thickness, the air bag shows good
foldability, and is excellent in storability.
[0074] In the two coating layers in the present invention, a
coupling agent composed of an organosilicon compound is preferably
added to improve the adhesive strength of the first layer silicone
composition. The following compounds can be used as the coupling
agent: a silane having a hydrolysable group; a compound having a
vinyl group, an acryloxy group, a methacryloxy group, an epoxy
group or an acid anhydride group that is bonded to the above silane
through a carbon atom. A coupling agent having a molecular weight
of 150 to 1,000 is usually used. A partially hydrolyzed product
and/or a hydrolyzed product mixture of such a silane can also be
used. Vinyltriacetoxysilane and
.gamma.-glycidoxypropyltrimethoxysilane, namely, mixture products
of a silane represented by the following chemical formula (1) are
preferably used. ##STR1##
[0075] More preferably, at least one compound represented by the
chemical formula (R.sub.4O).sub.4Si (wherein R is a hydrocarbon
group, the four Rs may be the same or different from each other,
and R may be, for example, ethyl, propyl, vinylmethyl, cyclohexyl,
or the like) is contained as the coupling agent.
[0076] One type of a coupling agent may be used. Alternatively, two
types or more than two types of silanes in a mixture, or reaction
products, or partially hydrolyzed products, or a partially
hydrolyzed product mixture of the silanes in a mixture may also be
used.
[0077] The coupling agent composed of an organosilicon compound is
contained in the silicone composition in an amount of preferably
0.1 to 4.5% by weight, more preferably 0.5 to 3% by weight. When
the amount is less than 0.1% by weight, a satisfactory adhesive
strength of the coating exerted on the woven fabric surface cannot
be obtained sometimes. Moreover, the adhesive strength sometimes
becomes insufficient after wet heat aging and cooling-heating cycle
aging. When the amount exceeds 4.5% by weight, bubbles are
sometimes generated during heat treatment to worsen the product
surface quality. As a result, the internal pressure retention of
the air bag during deployment thereof sometimes becomes
insufficient.
[0078] In the two coating layers in the present invention, the
tensile elongation after curing of the silicone composition in the
first silicone coating layer is 350% or less. The coupling agent
that is composed of an organosilicon compound and that is added to
improve the adhesion improves an adhesive strength exerted on the
woven fabric surface, and at the same time lowers the tensile
elongation of the silicone composition after curing.
[0079] In the two coating layers in the present invention, the
diorganopolysiloxane having a SiC-bonded vinyl group at a terminal
unit and contained in the silicone composition in the first
silicone coating layer is mainly a diorganopolysiloxane represented
by the following general formula:
(CH.sub.2.dbd.CH).sub.xSiR.sub.(3-x)--O(SiR.sub.2O).sub.n1--SiR.sub.(3-x)-
(CH.dbd.CH.sub.2).sub.x wherein R represents hydrocarbon groups
preferably having 1 to 18 carbon atoms, R may be substituted with
other atoms or functional groups, R may be of the same hydrocarbon
groups or a mixture of different hydrocarbon groups, x is 1, 2 or
3, and n1 is a numerical value necessary for the
diorganopolysiloxane to have an average viscosity of 1,000 to
100,000 mPas at 25.degree. C.
[0080] The viscosity of the diorganopolysiloxane contained in the
silicone composition used in the first layer is preferably from
5,000 to 100,000 mPas, more preferably from 5,000 to 30,000 mPas.
The silicone composition in the first layer is used to improve the
adhesion to the woven fabric. When the viscosity is 100,000 mPas or
more, the silicone composition hardly permeate the woven fabric,
and a desired adhesive strength cannot be obtained sometimes.
[0081] In the two coating layers in the present invention, the
diorganopolysiloxane having a SiC-bonded vinyl group at a terminal
unit and contained in the silicone composition in the second
silicone coating layer is mainly a diorganopolysiloxane represented
by the following general formula:
(CH.sub.2.dbd.CH).sub.xSiR.sub.(3-x)--O(SiR.sub.2O).sub.n2--SiR.sub.(3-x)-
(CH.dbd.CH.sub.2).sub.x wherein R represents hydrocarbon groups
preferably having 1 to 18 carbon atoms, R may be substituted with
other atoms or functional groups, R may be of the same hydrocarbon
groups or a mixture of different hydrocarbon groups, x is 1, 2 or
3, preferably 1, and n2 is a numerical value necessary for the
diorganopolysiloxane to have an average viscosity of 50,000 to
1,000,000 mPas at 25.degree. C.
[0082] The second silicone coating layer in the present invention
performs the task of shielding an air leakage from the air bag. The
deployment air bag is usually deployed on a very short time scale
of 30 msec or less. The internal pressure during the deployment is
80 kPa or more, and a very large impact occurs on the coating film
forming the air bag. When the silicone composition used in the
second layer is inappropriate, the coating film is broken by the
impact, causing air leakage, and thus the air bag cannot carry out
its function.
[0083] In order to absorb the impact, and make the deployment
excellent, namely, in order to make the logarithmic decrement fall
in the range of 0.01 to 0.10, it is particularly preferred to make
the average viscosity of the diorganopolysiloxane contained in the
silicone composition used in the second layer fall in the range of
50,000 to 1,000,000 mPas. The tensile elongation of the silicone
composition after curing obtained from the silicone composition
that contains the diorganopolysiloxane having such an average
viscosity is preferably 400% or more, more preferably 500 to
1,000%, most preferably 800% or less.
[0084] The best structure of the coating layers in the present
invention comprises two silicone coating layers each having
physical properties different from the others in the cross section
of the film-forming layers on the woven fabric surface. Moreover,
the coating layers may also be multi-layers exceeding two layers
formed by further lamination.
[0085] An SPM (Scanning Probe Microscope) can clearly distinguish a
difference in physical properties between a crosslinked and cured
silicone in a film-forming state on a woven fabric surface and
another crosslinked and cured silicone therein. When the cross
section of a coating layer is measured in a tapping mode, a
difference in elastic properties of the coating layer can be
observed as a difference in a phase value. When the surface of a
sample is tapped with a probe in the form of a cantilever while the
probe is being controlled so that it is vibrated at a constant
amplitude, the relationship between an applied vibration
displacement and a vibration displacement of the probe tip is
measured as a phase. A probe displacement on a hard surface is
large, and as a result, the phase is observed to be large. When the
phase is mapped, a phase image indicating an elasticity difference
is obtained.
[0086] In the measurement of a cross section of the coating layer
in the present invention, it is preferred that there be a distinct
phase difference between the first layer and the second layer on
the woven fabric surface, and that a phase image of two layers be
obtained. A distinct phase difference between two layers signifies,
for example, that there is a phase ratio of 1/1 to 1/2.5 in terms
of an average phase ratio. Tapping conditions can be suitably
selected so that an elasticity difference becomes outstanding. Hard
tapping conditions are preferably employed. For example, an
amplitude decrement under tapping conditions is from 15 to 40%,
preferably about 35%.
[0087] Various types of probes can be used. For example, a probe
that has a spring constant of 20 to 100 N/m, the tip of which is
formed out of a silicon single crystal, and the tip portion of
which has a radius of curvature of 10 to 20 mm can be used.
[0088] The average phase .delta. of the first layer and the average
phase .delta. of the second layer from the woven fabric surface
preferably have the following relationship: (.delta. of first
layer)>(.delta. of second layer)
[0089] In the present invention, it is more preferable that the
ratio of the average phase be from 1.1 to 2.5. A layer structure in
which a difference in physical properties is distinctly present
makes the following compatible: the logarithmic decrement of the
coating film is high; the coating film is hardly broken; and the
coating film is well bonded to the woven fabric surface. As a
result, functions of the air bag such as an internal
pressure-retaining function can be maintained under various
environmental conditions.
[0090] That is, the first layer is a hard layer, and the second
layer is a soft layer. That the second layer is soft contributes to
a large entire logarithmic decrement. Softness as a whole is
necessary for retaining the air tightness for a long time. The
first layer is a highly crosslinked silicone having relatively hard
properties, and carries out the function of bonding the coating
layer to the woven fabric.
[0091] It is more preferable that the ratio of the average phase
.delta. be in the following relationship: 1.1<[(.delta. of first
layer)/(.delta. of second layer)]<2.5
[0092] That is, the layer structure is as follows: the first layer
is a hard layer, and the second layer is a soft layer, a difference
in the physical properties between both layers being distinct.
There is a large difference in physical properties between the
first layer and the second layer; that the coating film is hardly
broken and that the coating film is bonded well to the woven fabric
surface are made highly compatible by making both layers perform
their respective tasks.
[0093] Furthermore, it is preferred in the present invention that
the ratio of an average film thickness D of the first layer to an
average film thickness D of the second layer on the woven fabric
surface be in the following relationship: 1/30<[(D of first
layer)/(D of second layer)]<1
[0094] The presence of the second soft layer having a thickness
equal to or greater than that of the first layer contributes to a
large logarithmic decrement. The flexibility of the coating layer
as a whole caused by the amount present of the second layer is
effective in retaining the air tightness for a long time. Although
it is satisfactory that the first layer be present in a minimum
amount as a coating layer to carry out the function of bonding, a
thickness of the first layer that ensures the uniform presence of
the layer over the woven fabric surface is necessary.
[0095] In the present invention, the surface of the second silicone
coating layer may be coated with a silicone coating composition as
a third layer. Provision of the third layer makes the deployment
speed of the air bag high. The silicone composition used for the
third layer contains known inorganic fillers such as calcium
carbonate, aluminum trihydrate, cabin black, diatomaceous earth,
silica, talc and mica. The silicone composition becomes effective
when the content of the inorganic filler is preferably 30% by
weight or more, more preferably from 30 to 60% by weight. A coating
amount of the third layer is preferably from 1 to 25 g/m.sup.2,
more preferably from 5 to 25 g/m.sup.2. When the coating amount is
25 g/m.sup.2 or less, making the third layer sufficiently light
weight is achieved, and no dropout of the inorganic fillers
occurs.
[0096] The hollow weave fabric for an air bag of the invention can
retain adhesive strength (the retention being a measure of
durability within an automobile) in wet heat aging (for 200 hr at
80.degree. C. and 95% RH) and cooling-heating cycle aging (30
cycles of the following A to C:
[0097] A) treatment of the sample at 125.degree. C. for 336 hr, and
cooling the sample at a rate of 2.degree. C./min;
[0098] B) treatment of the sample at -40.degree. C. for 24 hr, and
heating the sample at a rate of 2.degree. C./min; and
[0099] C) treatment of the sample at 85.degree. C. and 95% RH for
24 hr, and heating the sample at rate of 2.degree. C./min)
[0100] The sample having been subjected to the wet heat aging and
the cooling-heating cycle aging shows no delamination after scrub
testing (ISO 5981) 500 times or more.
[0101] The hollow weave fabric for an air bag of the present
invention can be used for an air bag installed in the front portion
of a driver's seat or an assistant driver's seat, and a
curtain-like air bag that can correspond to the collision the
vehicle encounters from the side or rollover of the vehicle. The
hollow weave fabric can especially be used for a curtain-like air
bag capable of retaining a pressurized gas for a given time.
[0102] There is no specific restriction on means for producing a
woven fabric used for the hollow weave fabric for an air bag of the
invention. The weaving machine should be an air-jet loom, a rapier
loom, a projectile loom, a multi-phase weaving machine, or the
like. A jacquard apparatus, a DOBBI apparatus, or the like
apparatus can be used as a machine for controlling the up and down
of a warp yarn. However, an electronic jacquard apparatus is
advantageous in productivity, quickness in design alteration and
preciseness of a design. Although there is no specific restriction
on the number of feeders of a jacquard apparatus, an electronic
jacquard apparatus having as many feeders as from 2,000 to 14,000
feeders is preferred, because such an apparatus can precisely
correspond to designing a complicated shape.
[0103] In the present invention, the warp and weft dimensions or
the smoothness of the woven fabric surface can be set in desired
ranges by coating pretreatments such as a conventional
scouring-setting step, a setting step alone or calendaring.
[0104] In the present invention, the silicone composition for the
first layer with which the woven fabric surface is coated contains
at least the following elements (a) to (d):
[0105] (a) an organopolysiloxane containing a SiC-bonded vinyl
group at a terminal unit and having a viscosity of 1,000 to 100,000
mPas at 25.degree. C.;
[0106] (b) an organopolysiloxane having at least 3 Si-bonded
hydrogen atoms;
[0107] (c) a catalyst that promotes addition of Si-bonded hydrogen
atoms to an aliphatic multiple bond; and
[0108] (d) a coupling agent composed of an organosilicon
compound.
[0109] The diorganopolysiloxane (a) containing a SiC-bonded vinyl
group at a terminal unit is represented by the following general
formula:
(CH.sub.2.dbd.CH).sub.xSiR.sub.(3-x)--O(SiR.sub.2O).sub.n1--SiR.sub.(3-x)-
(CH.dbd.CH.sub.2).sub.x wherein R represents hydrocarbon groups
preferably having 1 to 18 carbon atoms, R may be substituted with
other atoms or functional groups, R may be of the same hydrocarbon
groups or a mixture of different hydrocarbon groups, x is 1, 2 or
3, preferably 1, and n1 is a numerical value necessary for the
diorganopolysiloxane to have an average viscosity of 5,000 to
100,000 mPas at 25.degree. C.
[0110] The viscosity of the diorganopolysiloxane (a) is preferably
from 5,000 to 50,000 mPas, more preferably from 5000 to 30,000
mPas. The silicone composition for the first layer is used to
improve the adhesion to the woven fabric. When the viscosity
exceeds 100,000 mPas, the silicone composition hardly permeates the
woven fabric, and a desired adhesive strength cannot be obtained
sometimes.
[0111] Preferred examples of the hydrocarbon group R include an
alkyl group such as a methyl group, an ethyl group, an n-propyl
group, an isopropyl group, a butyl group, an octyl group, a
tetradecyl group or an octadecyl group, an alicyclic hydrocarbon
group such as a cyclopentyl group, a cyclohexyl group or a
methylcyclohexyl group, an aryl group such as a phenyl group, an
alkaryl group such as a tolyl group and an aralkyl group such as a
benzyl group or a phenylethyl group.
[0112] Preferred examples of the substituted hydrocarbon group
include halogenated groups such as a 3,3,3-trifluoropropyl group,
3-chloropropyl group or a chlorophenyl group. A cyanoalkyl group
such as a cyanoethyl group may also be included. A group having an
unsaturated aliphatic group such as a vinyl group, an allyl group,
a hexenyl group or a cyclohexenyl group may also be included.
[0113] The hydrocarbon group R is preferably a hydrocarbon group
having 1 to 10 carbon atoms, more preferably at least 80% of
organic groups represented as R are methyl groups.
[0114] The above organopolysiloxane may be a group of the same
copolymers. It may also be a mixture of different copolymers each
having a polymerization degree equal to or different from those of
the others. When the diorganopolysiloxane has diorganopolysiloxane
units different from each other, the units may be randomly
distributed or they may be distributed in blocks.
[0115] The organopolysiloxane having at least 3 Si-bonded hydrogen
atoms is represented by the following general formula:
(CH.sub.3).sub.3SiO--(SiHRO).sub.o--(SiR.sub.2O).sub.p--Si(CH.sub.3).sub.-
3 wherein R represents hydrocarbon groups preferably having 1 to 18
carbon atoms, R may be substituted with other atoms or functional
groups, R may be of the same hydrocarbon groups or a mixture of
different hydrocarbon groups, x is 1, 2 or 3, and o and p are
present in a ratio of 1:0 to 1:2.0, preferably 1:0 to 1:7.
[0116] The total of o and p is 10 to 1,000, preferably from 20 to
200, more preferably from 30 to 100. For an organopolysiloxane
having at least 3 Si-bonded hydrogen atoms per molecule, an
organopolysiloxane having no Si valence saturated with a hydrogen
atom and a siloxane oxygen atom is preferably saturated with a
methyl group, an ethyl group or a phenyl group. However, the
organopolysiloxane may contain all the groups described as R
mentioned above.
[0117] Any known catalyst that promotes the reaction can be used as
the catalyst for promoting addition of Si-bonded hydrogen atoms to
an aliphatic multiple bond (c). Examples of such catalysts include
finely divided metallic platinum (platinum sol), ruthenium,
rhodium, palladium and iridium in which these metals may be
supported on a solid carrier such as silicon dioxide, aluminum
oxide or activated carbon, a ceramic material, an oxide mixture or
a hydroxide mixture.
[0118] Compounds or complexes of these metals, such as
platinum-olefin complexes, platinum-alcohol complexes such as
Speyers Catalyst, platinum-alcoholate complexes, platinum-ether
complexes, platinum-aldehyde complexes, platinum-ketone complexes
including the reaction product of H.sub.2PtCl.sub.6.6H.sub.2O and
cyclohexanone, platinum-vinylsiloxane complexes and in particular
platinum-divinyltetramethyldisiloxane complexes with or without a
detectable content of inorganically bonded halogen,
bis(.gamma.-picoline)-platinum dichloride, trimethylenepyridine
platinum dichloride, dicyclopentadieneplatinum dichloride, dimethyl
sulfoxide-ethyleneplatinum (II) dichloride and reaction products of
platinum tetrachloride dissolved in 1-octene and sec-butylamine may
also be used as the catalysts. Platinum compounds are particularly
preferred catalysts.
[0119] The above catalysts can also be used singly or as a mixture.
When a platinum catalyst is used, the catalyst can be used in an
amount of 3 to 500 ppm as platinum based on the siloxane content,
preferably 10 to 200 ppm based thereon.
[0120] Examples of the coupling agent composed of an organosilicon
compound (d) include a silane having a hydrolysable group, or a
silane having a vinyl, acryloxy, methacryloxy, epoxy or acid
anhydride group bonded to a silicon atom of the silane through a
carbon atom. Hydrolyzed products and/or a mixture of hydrolyzed
products of such a silane can also be used. Vinyltriacetoxysilane
and .gamma.-glycidoxypropyl-trimethoxysilane, namely, the reaction
products of the silane represented by the above chemical formula
(I) are preferably used.
[0121] One type of coupling agent can also be used. However, a
mixture of two types or more than two types of silanes or reaction
products of the silanes, or partially hydrolyzed products or a
mixture of hydrolyzed products thereof can also be used. The
tensile elongation after curing of the above silicone composition
for the first layer is preferably 350% or less.
[0122] In the present invention, the silicone composition for the
second layer with which the surface of the first layer is coated
contains at least the following (A) to (C):
[0123] (A) an organopolysiloxane containing a Si--C bonded vinyl
group at a terminal unit, and having a viscosity of 50,000 to
1,000,000 mPas at 25.degree. C.;
[0124] (B) an organopolysiloxane having at least 3 Si-bonded
hydrogen atoms; and
[0125] (C) a catalyst for promoting addition of Si-bonded hydrogen
atoms to aliphatic multiple bonds.
[0126] The diorganopolysiloxane having a SiC-bonded vinyl group at
a terminal unit and contained in the silicone composition for the
second layer (A) is a diorganopolysiloxane represented by the
following general formula:
(CH.sub.2.dbd.CH).sub.xSiR.sub.(3-x)--O(SiR.sub.2O).sub.n2--SiR-
.sub.(3-x)(CH.dbd.CH.sub.2).sub.x wherein R represents hydrocarbon
groups preferably having 1 to 18 carbon atoms, R may be substituted
with other atoms or functional groups, R may be of the same
hydrocarbon groups or a mixture of different hydrocarbon groups, x
is 1, 2 or 3, preferably 1, and n2 is a numerical value necessary
for the diorganopolysiloxane to have an average viscosity of 50,000
to 1,000,000 mPas at 25.degree. C.
[0127] The organopolysiloxane having at least 3 Si-bonded hydrogen
atoms (B) and the catalyst for promoting addition of Si-bonded
hydrogen atoms to aliphatic multiple bonds (C) may be similar to
(b) and (c), respectively, contained in the silicone composition
for the first layer.
[0128] The warp yarn density and the weft yarn density of the
hollow weave fabric for an air bag of the present invention are
preferably each from 40 to 100/2.54 cm. When the densities are each
less than 40/2.54 cm, the air bag may burst during deployment
thereof due to insufficient tenacity for a yarn of 500 dtex or
less. When the densities each exceed 100/2.54 cm, a tenacity
sufficient for an air bag deployment is obtained for a yarn of 150
dtex or more.
[0129] The system of the silicone composition used for the first
layer of the two coating layers in the present invention may be any
system such as a dope prepared by diluting the silicone composition
with an organic solvent, a dope in which a silicone is emulsified
and a dope without a solvent. Although there is no specific
limitation thereon, preferably the system is a dope without a
solvent. The composition is preferably applied with a floating
knife, a roll-on-knife or dipping. When the silicone composition is
applied, the coating is continuously heat treated at 120 to
200.degree. C. for 10 to 600 sec to be cured by a crosslinking
reaction of the silicone.
[0130] The system of the silicone composition used for the second
layer in the present invention may be any system such as a dope
prepared by diluting the silicone composition with an organic
solvent, a dope in which silicone is emulsified and a dope without
a solvent. Although there is no specific limitation thereon,
preferably the system is a dope substantially without a solvent.
The silicone composition is preferably applied with a floating
knife, a roll-on-knife or a comma coater. When the silicone
composition is applied, the coating is continuously heat treated at
120 to 200.degree. C. for 10 to 600 sec to be cured by a
crosslinking reaction of the silicone.
[0131] In the present invention, the silicone composition used for
the third layer to decrease the surface friction has an average
viscosity of 100 to 10,000 mPas or more at 25.degree. C., and
should contain an organopolysiloxane having a SiC-bonded vinyl
group, an organopolysiloxane having at least 3 Si-bonded hydrogen
atoms, a catalyst for promoting addition of Si-bonded hydrogen
atoms to aliphatic multiple bonds (hydrosilylation reaction), and
30% by weight or more of an inorganic filler.
[0132] Calcium carbonate, aluminum trihydrate, carbon black,
diatomaceous earth, and the like, that are known can be used as the
inorganic fillers. Although there is no specific limitation on the
coating method, gravure coating can be preferably used.
[0133] In the present invention, the silicon composition may be
allowed to contain known fillers for reinforcement. Examples of the
fillers include silica, organosilicon resins, titania, quartz
powder and aluminosilicate. Of these materials, silica and
organosilicon resins are preferred. Fumed silica or precipitation
silica can be used as the silica. The average particle size of the
silica is from 0.1 to 20 .mu.m, and the BET surface area is 50
m.sup.2/g or more. Moreover, a silicone resin represented by the
general formula
(R.sub.3SiO.sub.1/2).sub.a(R.sub.3SiO.sub.3/2).sub.b can be
employed as the organosilicon resin.
[0134] In addition, in the above general formula, R represents a
methyl group, a phenyl group, a vinyl group or a hydrogen atom, and
the ratio of a to b is selected so that the viscosity of silicone
resin falls in the range of a viscosity of 30 to 300,000 mPas.
[0135] Furthermore, the silicone composition may be allowed to
contain additives such as chain extenders, dyes, adhesion-promoting
agents, coloring agents, pigments, viscosity-adjusting agents, bath
life extenders, softening agents, curing inhibitors, flame
retardants, anti-oxidation agents and catalyst-activating
agents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0136] FIG. 1 is a schematic view of a base fabric for an air bag
in examples.
[0137] FIG. 2 is an SEM photograph of a cross section of a base
fabric for an air bag in Example 18.
[0138] FIG. 3 is an SPM phase image of a cross section of a base
fabric for an air bag in Example 18.
DESCRIPTION OF REFERENCE NUMERALS
[0139] 1 hollow weave fabric for an air bag [0140] 2 seam zone
[0141] 3 double-layer hollow weave portion [0142] 4 single-layer
portion [0143] 5 fluid inlet portion [0144] 6 partially knotted
portion [0145] F base woven fabric [0146] G first layer [0147] H
second layer [0148] S third layer (surface layer)
EXAMPLES
[0149] The present invention is further explained below by making
reference to examples. In addition, measuring methods, evaluation
methods, and the like, are as explained below.
[0150] (1) Total Size, Single Filament Size
[0151] Measurements are made in accordance with JIS L 1096.
[0152] (2) Weight of Bag Portion (Fabric Weight)
[0153] Measurements are made in accordance with JIS L 1096.
[0154] (3) Logarithmic Decrement
[0155] The logarithmic decrement is measured with a rigid pendulum
type physical property tester (trade name of RPT-3000, manufactured
by A and D Co., Ltd.). A small piece, 8.times.4 cm, cut out of a
hollow weave fabric for an air bag is set on a measurement table so
that the coating face is on the measurement blade side. A knife
edge type RB200 frame of the blade specification is used, and the
measurement conditions are as follows: measurement intervals of 6
sec; pendulum adsorption intervals (to make the pendulum stand
still) of 2 sec; a pendulum period of 0.6 sec; heating rate of
10.degree. C./min; and a temperature measurement range of -100 to
150.degree. C. The logarithmic decrement is read at 20.degree. C.
in the measurement.
[0156] (4) Viscosity of a Silicone Composition
[0157] Measurements are made with a Brookfield viscometer
[0158] (5) Elongation of the Resin after Curing a Silicone
Composition
[0159] Measurements are made in accordance with JIS K 6249
[0160] (6) Measurements with an SPM
[0161] A small piece is cut out from a hollow weave fabric for an
air bag, and embedded in an epoxy resin. Cross-sectional sample is
prepared using a cryo microtome so that a base fabric cross
sections are obtained in the warp yarn direction and in the weft
one.
[0162] (Conditions Under which Samples are Prepared)
[0163] Ultramicrotome ULTRACUT N (trade name, manufactured by
Reichert)
[0164] Cryo unit FC 4E (trade name, manufactured by Reichert)
[0165] Setting temperature: -130.degree. C. for a sample;
-130.degree. C. for a glass knife
[0166] Next, a cross section of the base fabric is measured with an
SPM (Scanning Probe Microscope).
[0167] Measurement apparatus: Nano Scope IV D3100 (trade name,
manufactured by Digital Instruments)
[0168] Measurement mode: Tapping mode/resonance frequency of 276.6
kHz
[0169] Probe: NCH type silicone single crystal probe
[0170] (Conditions Under which Measurements are Made)
[0171] Scan angle: 0.degree.
[0172] Scan rate: 0.3 Hz
[0173] Digital resolution (Number of sampling): 256.times.256
[0174] Control of amplitude level (Target amplitude): 1.6 V
[0175] Amplitude decrement: 31.25%
[0176] Integral gain: 0.65
[0177] Proportional gain: 1.5
[0178] It is confirmed that neither significant unevenness nor
marked steps on the surface are present. A macroscopic inclination
correction on the surface is made on the data, and phase mapping is
carried out to give a phase image. Moreover, the average data of
the phase is obtained.
[0179] Furthermore, the form of a similar cross-sectional sample is
observed with an SEM.
[0180] FE-SEM S-4700 (trade name, manufactured by Hitachi, Ltd.
[0181] Acceleration voltage: 1 to 5 kV
[0182] Working distance: 12 to 13 mm
[0183] (7) Compactness (Storability)
[0184] A hollow weave fabric for an air bag having a shape as shown
in FIG. 1 is folded in a bellows-like manner in the direction from
A to B with a width of 5.08 cm (2 inches). The folded airbag is
then placed on a flat table. A glass plate, 50 mm.times.50 mm, is
placed on the air bag near the central portion thereof, and a load
is applied thereto with a 1 kg weight. The average thickness X (mm)
is measured 30 minutes after applying the load.
[0185] (8) Internal Pressure Retention (Deployability), Maximum
Pressure Reaching Time (Deployability)
[0186] A hollow weave fabric for an air bag having a shape as shown
in FIG. 1 is folded in a bellows-like manner in the direction from
A to B with a width of 5.08 cm (2 inches). A monofilament of 100
dtex is wound around the folded air bag at 10 cm intervals so that
the folded air bag does not collapse. The hollow weave fabric for
an air bag is connected to the tip of a tank having a capacity of
300 liters and an internal pressure of 900 kPa through a metal
tube. An electromagnetic valve attached near the tip of the tank is
instantaneously opened and closed. A variation in the internal
pressure of the hollow weave fabric for an air bag is then examined
with a pressure sensor attached to the tube on the side of the
hollow weave fabric for an air bag.
[0187] When the internal pressure retention is 50% or more of the
initial internal pressure after 8 sec, the air bag is accepted. The
number of measurements is 10. When a minimum internal pressure
retention does not exceed 50% even once, the air bag is considered
as having a problem. Moreover, the deployability of the air bags is
compared by the maximum pressure reaching time.
[0188] (9) Scrub Test
[0189] Measurements are made in accordance with ISO 5981.
[0190] The dimensions of the sample are 50 mm W (warp yarn
direction).times.100 mm L (weft yarn direction). A grip line is
depicted in the weft yarn direction at two sites each 27 mm apart
from one end of the sample.
[0191] Setting of the sample: the sample is placed so that the
coating face is on the upper side; two gripping clamps are placed
so that they face each other and the clamp edges coincide to the
respective gripping lines, and made to grip the sample so that the
central portion 46 mm long in the 100 mm L direction is situated
between both clamps. The central portion 46 mm long is clearly
folded, and a pressure load of 10 N is applied.
[0192] Establishment of testing criteria: visible delamination of
the silicone layer is confirmed at every 100 cycles, and the number
of cycles at which the delamination is produced is recorded. When
no delamination is observed, the test is conducted until 2,000
cycles, and then completed.
[0193] (10) Wet Heat Aging
[0194] A hollow weave fabric for an air bag after coating was
treated at 80.degree. C. and 95% RH for 200 hr.
[0195] (11) Cooling-Heating Cycle Aging
[0196] A hollow weave fabric for an air bag after coating was
treated for 30 cycles under the following conditions A to C: [0197]
A) the fabric is treated at 125.degree. C. for 336 hr, and cooled
at a rate of 2.degree. C./min; [0198] B) the fabric is treated at
-40.degree. C. for 24 hr, and heated at a rate of 2.degree. C./min;
and [0199] C) the fabric is treated at 85.degree. C. and 95% RH for
24 hr, and heated at a rate of 2.degree. C./min.
Example 1
[0200] A nylon 66 fiber having a total size of 235 dtex and a
single filament size of 3.3 dtex was used as a warp yarn and a weft
yarn, and a gray fabric having a design as shown in FIG. 1 was
prepared with an electronic jacquard apparatus and a rapier loom.
The gray fabric was then scoured and set. The seam zone formed a
reversible figured weave when seen from the bag portion side. A
double-layer hollow weave portion was then prepared from two yarns.
Moreover, a 2/2 basket weave pattern was formed as a single-layer
portion out of 6 yarns.
[0201] Next, the fabric was coated with a liquid silicone
composition in an amount of 50 g/m.sup.2 on one side using a
roll-on-knife coater, and heat treated at 180.degree. C. for 1
minute in a drying machine. The fabric was similarly coated with a
liquid silicone composition in an amount of 50 g/m.sup.2 on the
other side, and heat treated at 180.degree. C. for 1 minute in a
drying machine. The bag portion after coating had a warp yarn
density of 72 ends/2.54 cm and a weft yarn density of 72 picks/2.54
cm.
[0202] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 1. The air bag was excellent in compactness, and showed a
good internal pressure retention, and a quick deployment speed.
[0203] The liquid silicone composition used herein was produced as
explained below.
[0204] (1) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 150,000 mPas at
25.degree. C. were mixed with a kneader. Next, 0.03 part by weight
of ethynylcyclohexanol and 0.07 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were added to the mixture with stirring.
[0205] (2) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 150,000 mPas at
25.degree. C. were mixed with a kneader. A hydrogen siloxane in an
amount of 8 parts by weight having a viscosity of about 1,000 mPas
at 25.degree. C. was further added to the mixture with
stirring.
[0206] The mixture produced in (1) mentioned above in an amount of
44 parts by weight, 52 parts by weight of the mixture produced in
(2) mentioned above, 1.5 parts by weight of an organopolysiloxane
containing a Si--H bond and having a viscosity of about 20 mPas at
25.degree. C., 0.9 part by weight of tetraethoxysilane and 0.9 part
by weight of a platinum-divinyltetramethyldisiloxane complex
containing 1% by weight of platinum were mixed with a kneader to
give the liquid silicone composition.
Example 2
[0207] The fabric obtained in the same manner as in Example 1 was
coated with a liquid silicone composition in an amount of 50
g/m.sup.2 on one side using a roll-on-knife coater, and heat
treated at 180.degree. C. for 1 minute in a drying machine. The
fabric was similarly coated with a liquid silicone composition in
an amount of 50 g/m.sup.2 on the other side, and heat treated at
180.degree. C. for 1 minute in a drying machine. The bag portion
after coating had a warp yarn density of 72 ends/2.54 cm and a weft
yarn density of 72 picks/2.54 cm.
[0208] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 1. The air bag was excellent in compactness, and showed
good internal pressure retention, and quick deployment speed.
[0209] The liquid silicone composition used herein was produced as
explained below.
[0210] (1) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 5,000 mPas at 25.degree.
C. were mixed with a kneader. Next, 0.03 part by weight of
ethynylcyclohexanol and 0.07 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were added to the mixture with stirring.
[0211] (2) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 5,000 mPas at 25.degree.
C. were mixed with a kneader. A hydrogen siloxane in an amount of 8
parts by weight having a viscosity of about 1,000 mPas at
25.degree. C. was further added to the mixture with stirring.
[0212] The mixture produced in (1) mentioned above in an amount of
44 parts by weight, 52 parts by weight of the mixture produced in
(2) mentioned above, 1.5 parts by weight of an organopolysiloxane
containing a Si--H bond and having a viscosity of about 20 mPas at
25.degree. C., 0.9 part by weight of tetraethoxysilane and 0.9 part
by weight of a platinum-divinyltetramethyldisiloxane complex
containing 1% by weight of platinum were mixed with a kneader to
give the liquid silicone composition.
Comparative Example 1
[0213] The fabric obtained in the same manner as in Example 1 was
coated with a liquid silicone composition in an amount of 50
g/m.sup.2 on one side using a roll-on-knife coater, and heat
treated at 180.degree. C. for 1 minute in a drying machine. The
fabric was similarly coated with a liquid silicone composition in
an amount of 50 g/m.sup.2 on the other side, and heat treated at
180.degree. C. for 1 minute in a drying machine. The bag portion
after coating had a warp yarn density of 72 ends/2.54 cm and a weft
yarn density of 72 picks/2.54 cm.
[0214] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 1. Although the air bag was good in compactness, it showed
air leakage due to a low logarithmic decrement and a low internal
pressure retention.
[0215] The liquid silicone composition used herein was produced as
explained below.
[0216] (1) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 1,000 mPas at 25.degree.
C. were mixed with a kneader. Next, 0.03 part by weight of
ethynylcyclohexanol and 0.07 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were added to the mixture with stirring.
[0217] (2) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 1,000 mPas at 25.degree.
C. were mixed with a kneader. A hydrogen siloxane in an amount of 8
parts by weight having a viscosity of about 1,000 mPas at
25.degree. C. was further added to the mixture with stirring.
[0218] The mixture produced in (1) mentioned above in an amount of
44 parts by weight, 52 parts by weight of the mixture produced in
(2) mentioned above, 1.5 parts by weight of a hydrogen siloxane
having a viscosity of about 20 mPas at 25.degree. C., 0.9 part by
weight of tetraethoxysilane and 0.9 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were mixed with a kneader to give the liquid
silicone composition.
Comparative Example 2
[0219] In the same manner as in Example 1, a fabric was coated with
a liquid silicone composition in an amount of 150 g/m.sup.2 on one
side using a roll-on-knife coater, and heat treated at 180.degree.
C. for 1 minute in a drying machine. The fabric was similarly
coated with a liquid silicone composition in an amount of 150
g/m.sup.2 on the other side, and heat treated at 180.degree. C. for
1 minute in a drying machine. The bag portion after coating had a
warp yarn density of 72 ends/2.54 cm and a weft yarn density of 72
picks/2.54 cm.
[0220] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 1. The air bag had tucking properties due to a large
logarithmic decrement, and showed poor deployability.
[0221] In addition, the same liquid silicone composition as in
Example 1 was used herein.
Example 3
[0222] A nylon 66 fiber having a total size of 175 dtex and a
single filament size of 3.1 dtex was used as a warp yarn and a weft
yarn, and a gray fabric having a design as shown in FIG. 1 was
prepared with an electronic jacquard apparatus and a rapier loom.
The gray fabric was then subjected to a set-coat step to give a
double-layer hollow weave textured fabric having a warp yarn
density of 166 ends/2.54 cm and a weft yarn density of 166/2.54 cm.
The seam zone formed a reversible figured weave when seen from the
bag portion side. A double-layer hollow weave portion was then
prepared from two yarns. Moreover, a 2/2 basket weave pattern was
formed as a single-layer portion out of 8 yarns.
[0223] Next, the fabric was coated with a liquid silicone
composition in an amount of 35 g/m.sup.2 on one side using a
roll-on-knife coater, and heat treated at 180.degree. C. for 1
minute in a drying machine. The fabric was similarly coated with a
liquid silicone composition in an amount of 35 g/m.sup.2 on the
other side, and heat treated at 180.degree. C. for 1 minute in a
drying machine. The bag portion after coating had a warp yarn
density of 83 ends/2.54 cm and a weft yarn density of 83 picks/2.54
cm.
[0224] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 1. The air bag was excellent in compactness, and showed
good internal pressure retention, and quick deployment speed.
[0225] In addition, the same liquid composition as in Example 1 was
used.
Example 4
[0226] A nylon 66 fiber having a total size of 350 dtex and a
single filament size of 4.9 dtex was used as a warp yarn and a weft
yarn, and a gray fabric having a design as shown in FIG. 1 was
prepared with an electronic jacquard apparatus and a rapier loom.
The gray fabric was then scoured and set. The seam zone formed a
reversible figured weave when seen from the bag portion side. A
double-layer hollow weave portion was then prepared from two yarns.
Moreover, a 2/2 basket weave pattern was formed as a single-layer
portion out of 6 yarns.
[0227] Next, the fabric was coated with a liquid silicone
composition in an amount of 50 g/m.sup.2 on one side using a
roll-on-knife coater, and heat treated at 180.degree. C. for 1
minute in a drying machine. The fabric was similarly coated with a
liquid silicone composition in an amount of 50 g/m.sup.2 on the
other side, and heat treated at 180.degree. C. for 1 minute in a
drying machine. The bag portion after coating had a warp yarn
density of 59 ends/2.54 cm and a weft yarn density of 59 picks/2.54
cm.
[0228] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 1. The air bag was excellent in compactness, and showed
good internal pressure retention, and quick deployment speed.
[0229] In addition, the same liquid silicone composition as in
Example 1 was used herein.
Comparative Example 3
[0230] A nylon 66 fiber having a total size of 470 dtex and a
single filament size of 6.6 dtex was used as a warp yarn and a weft
yarn, and a gray fabric having a design as shown in FIG. 1 was
prepared with an electronic jacquard apparatus and a rapier loom.
The gray fabric was then scoured and set. The seam zone formed a
reversible figured weave when seen from the bag portion side. A
double-layer hollow weave portion was then prepared from two yarns.
Moreover, a 2/2 basket weave pattern was formed as a single-layer
portion out of 6 yarns.
[0231] Next, the fabric was coated with a liquid silicone
composition in an amount of 130 g/m.sup.2 on one side using a
roll-on-knife coater, and heat treated at 180.degree. C. for 1
minute in a drying machine. The fabric was similarly coated with a
liquid silicone composition in an amount of 130 g/m.sup.2 on the
other side, and heat treated at 180.degree. C. for 1 minute in a
drying machine. The bag portion after coating had a warp yarn
density of 59 ends/2.54 cm and a weft yarn density of 59 picks/2.54
cm.
[0232] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 1. Because the air bag was heavy and the logarithmic
decrement was high, the coating surface had tucking properties, and
the air bag showed poor deployability.
[0233] In addition, the same liquid silicone composition as in
Example 1 was used herein.
Example 5
[0234] A nylon 66 fiber having a total size of 175 dtex and a
number of filaments of 56 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0235] Next, the woven fabric was coated with a liquid silicone
composition, as a first layer, in an amount of 20 g/m.sup.2 on one
side using a floating knife coater, and heat treated at 180.degree.
C. for 1 minute in a drying machine.
[0236] The liquid silicone composition used herein was produced as
explained below.
[0237] (1) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 6,000 mPas at 25.degree.
C. were mixed with a kneader. Next, 0.03 part by weight of
ethynylcyclohexanol and 0.07 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were added to the mixture with stirring.
[0238] (2) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 6,000 mPas at 25.degree.
C. were mixed with a kneader. An organopolysiloxane in an amount of
8 parts by weight containing a Si--H bond and having a viscosity of
about 1,000 mPas at 25.degree. C. was further added to the mixture
with stirring.
[0239] The mixture produced in (1) mentioned above in an amount of
44 parts by weight, 51 parts by weight of the mixture produced in
(2) mentioned above, 1.5 parts by weight of an organopolysiloxane
containing a Si--H bond and having a viscosity of about 20 mPas at
25.degree. C., 2.0 parts by weight of tetraethoxysilane and 0.9
part by weight of a platinum-divinyltetramethyldisiloxane complex
containing 1% by weight of platinum were mixed with a kneader to
give the liquid silicone composition.
[0240] The first silicone coating layer surface was coated with a
liquid silicone composition, as a second coating layer, in an
amount of 60 g/m.sup.2, and heat treated at 180.degree. C. for 2
minutes in a drying machine.
[0241] The liquid silicone composition used herein was produced as
explained below.
[0242] (3) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 100,000 mPas at
25.degree. C. were mixed with a kneader. Next, 0.03 part by weight
of ethynylcyclohexanol and 0.07 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were added to the mixture with stirring.
[0243] (4) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 100,000 mPas at
25.degree. C. were mixed with a kneader. An organopolysiloxane in
an amount of 8 parts by weight containing a Si--H bond and having a
viscosity of about 1,000 mPas at 25.degree. C. was further added to
the mixture with stirring.
[0244] The mixture produced in (3) mentioned above in an amount of
45 parts by weight, 52 parts by weight of the mixture produced in
(4) mentioned above, 1.5 parts by weight of an organopolysiloxane
containing a Si--H bond and having a viscosity of about 20 mPas at
25.degree. C. and 0.9 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were mixed with a kneader to give the liquid
silicone composition.
[0245] Furthermore, the other side of the fabric was similarly
coated with the liquid silicone composition used for the above
first layer, and then with the liquid silicone composition used for
the above second layer; the coated fabric was then heat treated in
a drying machine. The bag portion after coating had a warp yarn
density of 83 ends/2.54 cm and a weft yarn density of 83 picks/2.54
cm.
[0246] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 2. The air bag was excellent in compactness, and showed
good internal pressure retention.
Example 6
[0247] A nylon 66 fiber having a total size of 235 dtex and a
number of filaments of 72 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0248] Both sides of the hollow weave fabric were coated with the
same silicone compositions as used in Example 5 in the same manner
as therein. The bag portion after coating had a warp yarn density
of 72 ends/2.54 cm and a weft yarn density of 72 picks/2.54 cm.
[0249] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 2. The air bag was excellent in compactness, and showed
good internal pressure retention.
Example 7
[0250] A nylon 66 fiber having a total size of 350 dtex and a
number of filaments of 108 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0251] Both sides of the hollow weave fabric were coated with the
same silicone compositions as used in Example 5 in the same manner
as therein. The bag portion after coating had a warp yarn density
of 60 ends/2.54 cm and a weft yarn density of 60 picks/2.54 cm.
[0252] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 2. The air bag was excellent in compactness, and showed
good internal pressure retention.
Example 8
[0253] A nylon 66 fiber having a total size of 470 dtex and a
number of filaments of 144 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0254] Both sides of the hollow weave fabric were coated with the
same silicone compositions as used in Example 5 in the same manner
as therein. The bag portion after coating had a warp yarn density
of 51 ends/2.54 cm and a weft yarn density of 51 picks/2.54 cm.
[0255] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 2. The air bag was excellent in compactness, and showed
good internal pressure retention.
[0256] Furthermore, a small piece sample was cut out from the
hollow weave fabric for an air bag, and SPM measurements were made
on the base fabric cross section. Two coating layers were observed
from the phase image. The average phase ratio was 1.23, and a
structure in which the elastic modulus of the second layer was low
in comparison with that of the first layer could be confirmed. The
average film thickness ratio was 0.30, the value being equivalent
to the coating amount ratio.
Comparative Example 4
[0257] A nylon 66 fiber having a total size of 110 dtex and a
number of filaments of 36 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0258] Both sides of the hollow weave fabric were coated with the
same silicone compositions as used in Example 5 in the same manner
as therein. The bag portion after coating had a warp yarn density
of 110 ends/2.54 cm and a weft yarn density of 110 picks/2.54
cm.
[0259] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 2. Although the air bag is good in compactness, it burst
during deployment. When the air bag was observed, it was seen that
the weaving yarns were broken.
Comparative Example 5
[0260] A nylon 66 fiber having a total size of 700 dtex and a
number of filaments of 108 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0261] Both sides of the hollow weave fabric were coated with the
same silicone compositions as used in Example 5 in the same manner
as therein. The bag portion after coating had a warp yarn density
of 38 ends/2.54 cm and a weft yarn density of 38 picks/2.54 cm.
[0262] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag thus obtained
were as shown in Table 2. Although the air bag did not burst during
deployment, it showed poor compactness.
Example 9
[0263] A nylon 66 fiber having a total size of 470 dtex and a
number of filaments of 144 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0264] Next, the woven fabric was coated with a liquid silicone
composition on one side, as a first layer, in an amount of 20
g/m.sup.2 using a floating knife coater, and heat treated at
180.degree. C. for 1 minute in a drying machine.
[0265] The liquid silicone composition used herein was produced as
explained below.
[0266] (1) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 6,000 mPas at 25.degree.
C. were mixed with a kneader. Next, 0.03 part by weight of
ethynylcyclohexanol and 0.07 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were added to the mixture with stirring.
[0267] (2) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 6,000 mPas at 25.degree.
C. were mixed with a kneader. An organopolysiloxane in an amount of
8 parts by weight containing a Si--H bond and having a viscosity of
about 1,000 mPas at 25.degree. C. was further added to the mixture
with stirring.
[0268] The mixture produced in (1) mentioned above in an amount of
46 parts by weight, 51 parts by weight of the mixture produced in
(2) mentioned above, 1.5 parts by weight of a hydrogen siloxane
having a viscosity of about 20 mPas at 25.degree. C., 0.3 part by
weight of 3-glycidoxypropyltriethoxysilane and 0.9 part by weight
of a platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were mixed with a kneader to give the liquid
silicone composition.
[0269] The first silicone coating layer surface was coated with a
liquid silicone composition, as a second coating layer, in an
amount of 60 g/m.sup.2 using a roll-on-knife coater, and heat
treated at 180.degree. C. for 2 minutes in a drying machine.
[0270] The liquid silicone composition used herein was produced as
explained below.
[0271] (3) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 100,000 mPas at
25.degree. C. were mixed with a kneader. Next, 0.03 part by weight
of ethynylcyclohexanol and 0.07 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were added to the mixture with stirring.
[0272] (4) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 100,000 mPas at
25.degree. C. were mixed with a kneader. An organopolysiloxane in
an amount of 8 parts by weight containing a Si--H bond and having a
viscosity of about 1,000 mPas at 25.degree. C. was further added to
the mixture with stirring.
[0273] The mixture produced in (1) mentioned above in an amount of
45 parts by weight, 52 parts by weight of the mixture produced in
(2) mentioned above, 1.5 parts by weight of a hydrogen siloxane
having a viscosity of about 20 mPas at 25.degree. C. and 0.9 part
by weight of a platinum-divinyltetramethyldisiloxane complex
containing 1% by weight of platinum were mixed with a kneader to
give the liquid silicone composition.
[0274] Furthermore, the other side of the fabric was similarly
coated with the liquid silicone composition used for the above
first layer, and then with the liquid silicone composition used for
the above second layer; the coated fabric was then heat treated in
a drying machine. The bag portion after coating had a warp yarn
density of 51 ends/2.54 cm and a weft yarn density of 51 picks/2.54
cm.
[0275] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 3. The air bag after wet heat aging and cooling-heating
cycle aging showed good scrub test results and good internal
pressure retention.
[0276] Furthermore, a small piece sample was cut out from the
hollow weave fabric for an air bag, and SPM measurements were made
on the base fabric cross section. The results are shown in Table 3.
Two coating layers were observed. A structure in which the elastic
modulus of the second layer was low in comparison with that of the
first layer could be confirmed. The average film thickness ratio
was equivalent to the coating amount ratio.
[0277] Moreover, Table 3 also shows the results of SPM measurements
in Examples 10 to 11 and Comparative Example 6 explained below.
Example 10
[0278] An air bag was prepared in the same manner as in Example 9,
except that the silicone composition for the first layer was
allowed to contain 1 part by weight of
3-glycidoxypropyltriethoxysilane. The properties of the air bag
thus obtained were as shown in Table 3. The air bag after wet heat
aging and cooling-heating cycle aging showed good scrub test
results and good internal pressure retention.
Example 11
[0279] An air bag was prepared in the same manner as in Example 9,
except that the silicone composition for the first layer was
allowed to contain 3 parts by weight of
3-glycidoxypropyltriethoxysilane. The properties of the air bag
thus obtained were as shown in Table 3. The air bag after wet heat
aging and cooling-heating cycle aging showed good scrub test
results and good internal pressure retention.
Comparative Example 6
[0280] An air bag was prepared in the same manner as in Example 9,
except that 3-glycidoxypropyltriethoxysilane was not added to the
silicone composition for the first layer, and that the coating
amount of the second layer was made 160 g/m.sup.2. The properties
of the air bag thus obtained were as shown in Table 3. The air bag
after wet heat aging and cooling-heating cycle aging showed poor
scrub test results and insufficient internal pressure
retention.
Comparative Example 7
[0281] An air bag was prepared in the same manner as in Example 9,
except that the silicone composition for the first layer was
allowed to contain 3 parts by weight of
3-glycidoxypropyl-triethoxysilane and that the coating amount of
the second layer was made 160 g/m.sup.2.
[0282] The properties of the air bag thus obtained are shown in
Table 3. The air bag after wet heat aging and cooling-heating cycle
aging showed scrub test results and an internal pressure retention
that were satisfactory to a certain degree. However, the air bag
was heavy, and showed poor compactness, as a result, had poor
handling characteristics.
Comparative Example 8
[0283] An air bag was prepared in the same manner as in Example 9,
except that the silicone composition for the first layer was
allowed to contain 5 parts by weight of
3-glycidoxypropyl-triethoxysilane and that the coating amount of
the second layer was made 160 g/m.sup.2. However, many bubbles were
generated on the coating surface during forming of the first
coating layer.
[0284] The properties of the air bag thus obtained are shown in
Table 3. The air bag after wet heat aging and cooling-heating cycle
aging showed poor scrub test results and insufficient internal
pressure retention.
Example 12
[0285] A nylon 66 fiber having a total size of 235 dtex and a
number of filaments of 72 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0286] Next, the woven fabric was coated with a liquid silicone
composition on one side, as a first layer, in an amount of 5
g/m.sup.2 using a floating knife coater, and heat treated at
180.degree. C. for 1 minute in a drying machine.
[0287] The liquid silicone composition used herein was produced as
explained below.
[0288] (1) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 6,000 mPas at 25.degree.
C. were mixed with a kneader. Next, 0.03 part by weight of
ethynylcyclohexanol and 0.07 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were added to the mixture with stirring.
[0289] (2) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 6,000 mPas at 25.degree.
C. were mixed with a kneader. An organopolysiloxane in an amount of
8 parts by weight containing a Si--H bond and having a viscosity of
about 1,000 mPas at 25.degree. C. was further added to the mixture
with stirring.
[0290] The mixture produced in (1) mentioned above in an amount of
46 parts by weight, 51 parts by weight of the mixture produced in
(2) mentioned above, 1.5 parts by weight of an organopolysiloxane
containing a Si--H bond and having a viscosity of about 20 mPas at
25.degree. C., 1.5 parts by weight of tetraethoxysilane and 0.9
part by weight of a platinum-divinyltetramethyldisiloxane complex
containing 1% by weight of platinum were mixed with a kneader to
give the liquid silicone composition.
[0291] The first silicone coating layer surface was coated with a
liquid silicone composition, as a second coating layer, in an
amount of 60 g/m.sup.2 using a roll-on-knife coater, and heat
treated at 180.degree. C. for 2 minutes in a drying machine.
[0292] The liquid silicone composition used herein was produced as
explained below.
[0293] (3) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 100,000 mPas at
25.degree. C. were mixed with a kneader. Next, 0.03 part by weight
of ethynylcyclohexanol and 0.07 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were added to the mixture with stirring.
[0294] (4) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 100,000 mPas at
25.degree. C. were mixed with a kneader. A hydrogen siloxane in an
amount of 8 parts by weight having a viscosity of about 1,000 mPas
at 25.degree. C. was further added to the mixture with
stirring.
[0295] The mixture produced in (1) mentioned above in an amount of
45 parts by weight, 52 parts by weight of the mixture produced in
(2) mentioned above, 1.5 parts by weight of an organopolysiloxane
containing a Si--H bond and having a viscosity of about 20 mPas at
25.degree. C. and 0.9 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were mixed with a kneader to give the liquid
silicone composition.
[0296] Furthermore, the other side of the fabric was similarly
coated with the liquid silicone composition used for the above
first layer, and then with the liquid silicone composition used for
the above second layer; the coated fabric was then heat treated in
a drying machine. The bag portion after coating had a warp yarn
density of 72 ends/2.54 cm and a weft yarn density of 72 picks/2.54
cm.
[0297] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 4. The air bag after wet heat aging and cooling-heating
cycle aging showed good scrub test results and good internal
pressure retention.
Example 13
[0298] An air bag was prepared in the same manner as in Example 12,
except that the coating amount of the first layer and that of the
second layer were made 10 g/m.sup.2 and 40 g/m.sup.2,
respectively.
[0299] The properties of the air bag thus obtained were as shown in
Table 4. The air bag after wet heat aging and cooling-heating cycle
aging showed good scrub test results and good internal pressure
retention.
Example 14
[0300] An air bag was prepared in the same manner as in Example 12,
except that the coating amount of the first layer and that of the
second layer were made 10 g/m.sup.2 and 80 g/m.sup.2, respectively.
The properties of the air bag thus obtained were as shown in Table
4. The air bag after wet heat aging and cooling-heating cycle aging
showed good scrub test results and good internal pressure
retention.
Comparative Example 9
[0301] An air bag was prepared in the same manner as in Example 12,
except that the coating amount of the first layer and that of the
second layer were made 10 g/m.sup.2 and 220 g/m.sup.2,
respectively. The properties of the air bag thus obtained were as
shown in Table 4. The air bag after wet heat aging and
cooling-heating cycle aging showed good scrub test results and a
good internal pressure retention. However, the air bag was heavy,
had insufficient compactness, as a result, had poor handling
characteristics.
Example 15
[0302] An air bag was prepared in the same manner as in Example 12,
except that the coating amount of the first layer and that of the
second layer were made 30 g/m.sup.2 and 70 g/m.sup.2, respectively.
The properties of the air bag thus obtained were as shown in Table
4. The air bag after wet heat aging and cooling-heating cycle aging
showed good scrub test results and good internal pressure
retention.
Comparative Example 10
[0303] An air bag was prepared in the same manner as in Example 12,
except that the coating amount of the first layer and that of the
second layer were made 70 g/m.sup.2 and 30 g/m.sup.2, respectively.
The properties of the air bag thus obtained were as shown in Table
4. The air bag after wet heat aging and cooling-heating cycle aging
showed good scrub test results and good internal pressure
retention. However, the air bag was heavy, had insufficient
compactness, as a result, had poor handling characteristics.
Example 16
[0304] A nylon 66 fiber having a total size of 235 dtex and a
number of filaments of 72 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0305] Next, the fabric was coated in the same manner as in Example
5. The second silicone coating layer was then coated with a liquid
silicone composition as a third layer in an amount of 10 g/m.sup.2
using a gravure coater, and heat treated at 200.degree. C. for 30
sec in a drying machine. The bag portion after coating had a warp
yarn density of 72 ends/2.54 cm and a weft yarn density of 72
picks/2.54 cm.
[0306] The silicone composition used for the third layer was
produced as explained below.
[0307] (1) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 500 mPas at 25.degree.
C. were mixed with a kneader. Next, 0.03 part by weight of
ethynylcyclohexanol and 0.07 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum were added to the mixture with stirring.
[0308] (2) Hexamethyldisilazane-treated silica in an amount of 11
parts by weight and 33 parts by weight of a vinyl-terminated
polydimethylsiloxane having a viscosity of 500 mPas at 25.degree.
C. were mixed with a kneader. An organopolysiloxane in an amount of
8 parts by weight containing a Si--H bond and having a viscosity of
about 1,000 mPas at 25.degree. C. was further added to the mixture
with stirring.
[0309] The mixture produced in (1) mentioned above in an amount of
28 parts by weight, 30 parts by weight of the mixture produced in
(2) mentioned above, 1 part by weight of a hydrogen siloxane having
a viscosity of about 20 mPas at 25.degree. C., 1 part by weight of
an epoxysilane coupling agent, 0.5 part by weight of a
platinum-divinyltetramethyldisiloxane complex containing 1% by
weight of platinum, 20 parts by weight of calcium carbonate and 20
parts by weight of aluminum trihydrate were mixed with a kneader to
give the liquid silicone composition.
[0310] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 5. The air bag was excellent in compactness, and showed
good internal pressure retention.
Example 17
[0311] A nylon 66 fiber having a total size of 350 dtex and a
number of filaments of 108 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0312] The fabric was then coated in the same manner as in Example
16. The bag portion after coating had a warp yarn density of 60
ends/2.54 cm and a weft yarn density of 60 picks/2.54 cm.
[0313] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 5. The air bag was excellent in compactness, and showed
good internal pressure retention.
Example 18
[0314] A nylon 66 fiber having a total size of 470 dtex and a
number of filaments of 144 was used as a warp yarn and a weft yarn,
and a gray fabric having a design as shown in FIG. 1 was prepared
with an electronic jacquard apparatus and a rapier loom. The gray
fabric was then scoured and set. The seam zone formed a reversible
figured weave when seen from the bag portion side. A double-layer
hollow weave portion was then prepared from two yarns, and a 2/2
basket weave pattern was formed out of 4 yarns next thereto. A
double-layer hollow weave portion was then formed out of 4 yarns
next to the 2/2 basket weave pattern, and a 3/3 basket weave
pattern was formed out of 6 yarns next to the double-layer hollow
weave portion.
[0315] The two silicone compositions for respective two coating
layers used in Example 5 were similarly used. The woven fabric
surface was coated with the silicone composition for the first
coating layer, as a first coating layer, in an amount of 35
g/m.sup.2 using a floating knife coater, and heat treated at
180.degree. C. for 1 minute in a drying machine. The first silicone
coating layer was coated with the liquid silicone composition for
the second coating layer, as a second coating layer, in an amount
of 85 g/m.sup.2 using a roll-on-knife coater, and the woven fabric
was heat treated at 180.degree. C. for 2 minutes in a drying
machine.
[0316] The second coating layer was coated with the liquid silicone
composition used for the third coating layer in Example 16 in an
amount of 10 g/m.sup.2, as a third coating layer, using a gravure
coater, and the coated fabric was heat treated at 200.degree. C.
for 30 second in a drying machine. The bag portion after coating
had a warp yarn density of 57 ends/2.54 cm and a weft yarn density
of 49 picks/2.54 cm.
[0317] An air bag was prepared from the hollow weave fabric for an
air bag thus obtained. The properties of the air bag were as shown
in Table 5. The air bag was excellent in compactness, and showed
good internal pressure retention.
[0318] Furthermore, a small piece sample was cut out from the
hollow weave fabric for an air bag, and SPM measurements were made
on the base fabric cross section. The two coating layers and a
surface coating layer to become the third layer were observed from
the phase image. The distinct two layer structure is difficult to
discern in the SEM photograph. The average phase of the first layer
was 15.9, and that of the second layer was 9.6. The average phase
ratio was 1.66. That is, it could be confirmed that, in the
structure, the elastic modulus of the second layer was low in
comparison with that of the first layer. The average film thickness
ratio was 0.39, the value being approximately equivalent to the
coating amount ratio.
[0319] In addition, FIG. 2 shows an SEM photograph of a cross
section of the base fabric for an air bag, and FIG. 3 shows an SPM
phase image of a cross section of the base fabric for an air bag.
TABLE-US-00001 TABLE 1 Ex. 1 Ex. 2 C. Ex. 1 C. Ex. 2 Ex. 3 Ex. 4 C.
Ex. 3 Total size 235 235 235 235 175 350 470 of warp yarn (dtex)
Total size 235 235 235 235 175 350 470 of weft yarn (dtex) Warp
yarn 72 72 72 72 83 59 52 density (ends/2.54 cm) Weft yarn 72 72 72
72 83 59 52 density (picks/2.54 cm) Weight of 185 185 185 285 140
250 370 bag portion (g/m.sup.2) Logarithmic 0.038 0.021 0.008 0.121
0.019 0.042 0.131 decrement Compactness 48 50 47 65 40 53 85 (mm)
Maximum 150 140 160 260 120 165 310 pressure reaching time (msec)
Internal 90 85 41 93 87 89 94 pressure retention (average (%))
Internal 87-94 81-89 35*-48* 89-95 83-91 86-93 89-97 pressure
retention (min.-max. (%)) Note: In addition, the mark * in the
table indicates that the numerical value is at a level that causes
a problem.
[0320] TABLE-US-00002 TABLE 2 Ex. 5 Ex. 6 Ex. 7 Ex. 8 C. Ex. 4 C.
Ex. 5 Total size of warp 175 235 350 470 110 700 yarn (dtex) Total
size of weft 175 235 350 470 110 700 yarn (dtex) Warp yarn density
83 72 60 51 110 38 (ends/2.54 cm) Weft yarn density 83 72 60 51 110
38 (picks/2.54 cm) Weight of bag 210 230 270 300 185 350 portion
(g/m.sup.2) Logarithmic 0.027 0.029 0.029 0.029 0.031 0.033
decrement Compactness (mm) 53 57 60 62 46 72 Internal pressure 91
93 93 95 Burst 93 retention (average (%)) Internal pressure 89-96
91-95 92-95 93-97 Burst 92-95 retention (min.-max. (%))
[0321] TABLE-US-00003 TABLE 3 Ex. 9 Ex. 10 Ex. 11 C. Ex. 6 C. Ex. 7
C. Ex. 8 Total size of warp yarn 470 470 470 470 470 470 (dtex)
Total size of weft yarn 470 470 470 470 470 470 (dtex) Warp yarn
density 51 51 51 51 51 51 (ends/2.54 cm) Weft yarn density 51 51 51
51 51 51 (picks/2.54 cm) Weight of bag portion 300 300 300 400*
400* 400* (g/m.sup.2) Amount of coupling agent 0.3 1.0 3.0 0 3.0
5.0 in first layer (wt. %) Elongation of silicone 310 290 250 450
250 170 resin in first layer (%) Logarithmic decrement 0.019 0.017
0.014 0.18 0.031 0.023 Phase ratio (.delta. of first 1.21 1.32 1.60
1.09 -- -- layer)/(.delta. of second layer) Ratio of average film
0.30 0.30 0.30 0.11 -- -- thickness Compactness (mm) 62 63 64 73*
75* 76* Internal pressure 90 93 93 96 95 43* retention (average
(%)) Internal pressure 86-94 91-95 92-95 94-98 93-97 39*-48*
retention (min.-max. (%)) Internal pressure 89 93 93 35* 93 38*
retention after wet heat aging (average (%)) Internal pressure
85-93 91-95 92-95 20*-48* 90-95 33*-45* retention after wet heat
aging (min.-max. (%)) Internal pressure 90 93 93 43* 95 40*
retention after cooling- heating cycle aging (average (%)) Internal
pressure 89-94 91-95 92-95 35*-55* 93-97 36*-45* retention after
cooling- heating cycle aging (min.-max. %) Scrub test (times) 800
1200 2000 700 2000 200* Scrub test after wet heat 700 1000 2000 50*
2000 50* aging (times) Scrub test after cooling- 800 .gtoreq.1100
2000 150* 2000 50* heating cycle aging (times) Note: In addition,
the mark * in the table indicates that the numerical value is at a
level that causes a problem.
[0322] TABLE-US-00004 TABLE 4 Ex. 12 Ex. 13 Ex. 14 C. Ex. 9 Ex. 15
C. Ex. 10 Total size of warp yarn 235 235 235 235 235 235 (dtex)
Total size of weft yarn 235 235 235 235 235 235 (dtex) Warp yarn
density 72 72 72 72 72 72 (ends/2.54 cm) Weft yarn density 72 72 72
72 72 72 (picks/2.54 cm) Weight of bag portion 215 200 240 380* 250
420* (g/m.sup.2) Coating amount of first 5 10 10 10 70 70 layer
(g/m.sup.2) Coating amount of second 60 40 80 220 30 200 layer
(g/m.sup.2) Logarithmic decrement 0.023 0.024 0.028 0.133 0.019
0.141 Compactness (mm) 54 55 58 73* 59 78* Internal pressure 93 93
95 96 95 96 retention (average (%)) Internal pressure 90-95 91-95
94-97 94-98 93-97 94-98 retention (min.-max. (%)) Internal pressure
92 93 94 96 88 96 retention after wet heat aging (average (%))
Internal pressure 89-94 91-95 92-95 94-98 83-91 94-98 retention
after wet heat aging (min.-max. (%)) Internal pressure 92 93 93 96
89 96 retention after cooling- heating cycle aging (average (%))
Internal pressure 89-94 91-95 92-95 94-98 85-93 94-98 retention
after cooling- heating cycle aging (min.-max. %) Scrub test (times)
1200 2000 2000 500 1200 700 Scrub test after wet heat 900 2000 2000
400* 400* 400* aging (times) Scrub test after cooling- 1000 2000
2000 400* 500 500 heating cycle aging (times) Note: In addition,
the mark * in the table indicates that the numerical value is at a
level that causes a problem.
[0323] TABLE-US-00005 TABLE 5 Ex. 16 Ex. 17 Ex. 18 Total size of
warp yarn (dtex) 235 350 470 Total size of weft yarn (dtex) 235 350
470 Warp yarn density (ends/2.54 cm) 72 60 57 Weft yarn density
(picks/2.54 cm) 72 60 49 Weight of bag portion (g/m.sup.2) 240 280
370 Logarithmic decrement 0.023 0.021 0.015 Compactness (mm) 58 61
68 Internal pressure retention (average %) 93 93 94 Internal
pressure retention (min.-max. %) 91-95 92-95 93-96
INDUSTRIAL APPLICABILITY
[0324] Use of the hollow weave fabric for an air bag of the present
invention can provide a light weight air bag that retains its
internal pressure, and that is rapidly deployed. The hollow weave
fabric for an air bag of the present invention can be particularly
appropriately used for a curtain-like air bag that protects the
human body from the side face.
* * * * *