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.

Claims

1. A method for producing an air bag comprising a hollow weave fabric in which the periphery of a double-layer hollow weave portion is formed with a seam zone, wherein a warp yarn and a 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 a silicone coating layer formed of a silicone composition, the fabric shows a logarithmic decrement of 0.02 to 0.06 at 20 C. after the silicone coating layer is applied, and the air bag is capable of retaining 50% or more of an initial internal pressure 8 seconds after expansion and deployment when the initial internal pressure is a pressure obtained by inflating the air bag using a tank having a capacity of 300 liters and an internal pressure of 900 kPa, the method comprising: coating the silicone coating layer on both outer sides of the double-layer hollow weave portion, for a coating amount of the silicone composition per outer side of from 35 to 50 g/m.sup.2 as a solid component, wherein the silicone coating layer consists of one coating layer, on each of the both outer sides of the double-layer portion, the silicone coating layer is the only silicone coating layer coated thereon, the silicone composition contains an organopolysiloxane with a SiC-bonded vinyl group at a terminal end, the organopolysiloxane of the silicone coating layer has a viscosity of 5,000 to 150,000 mPa.Math.s at 25 C., and the silicone coating layer is formed with a floating knife or a roll-on-knife from a dope without a solvent.

2. A method for producing an air bag comprising a hollow weave fabric in which the periphery of a double-layer hollow weave portion is formed with a seam zone, wherein a warp yarn and a 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 a silicone coating layer formed of a silicone composition, the fabric shows a logarithmic decrement of 0.02 to 0.06 at 20 C. after the silicone coating layer is applied, and the air bag is capable of retaining 50% or more of an initial internal pressure 8 seconds after expansion and deployment, the method comprising: coating the silicone coating layer on both outer sides of the double-layer hollow weave portion, for a coating amount of the silicone composition per outer side of from 35 to 50 g/m.sup.2 as a solid component, such that the silicone composition permeates into the double-layer hollow weave portion, wherein the silicone coating layer consists of one coating layer, on each of the both outer sides of the double-layer portion, the silicone coating layer is the only silicone coating layer coated thereon, the silicone composition contains an organopolysiloxane with a SiC-bonded vinyl group at a terminal end, the organopolysiloxane of the silicone coating layer has a viscosity of 5,000 or more and less than 100,000 mPa.Math.s at 25 C., and the silicone coating layer is formed with a floating knife or a roll-on-knife from a dope without a solvent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view of a base fabric for an air bag in examples.

(2) FIG. 2 is an SEM photograph of a cross section of a base fabric for an air bag in Example 18.

(3) 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

(4) 1 hollow weave fabric for an air bag 2 seam zone 3 double-layer hollow weave portion 4 single-layer portion 5 fluid inlet portion 6 partially knotted portion F base woven fabric G first layer H second layer S third layer (surface layer)

EXAMPLES

(5) 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.

(6) (1) Total Size, Single Filament Size

(7) Measurements are made in accordance with JIS L 1096.

(8) (2) Weight of Bag Portion (Fabric Weight)

(9) Measurements are made in accordance with JIS L 1096.

(10) (3) Logarithmic Decrement

(11) 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, 84 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 C./min; and a temperature measurement range of 100 to 150 C. The logarithmic decrement is read at 20 C. in the measurement.

(12) (4) Viscosity of a Silicone Composition

(13) Measurements are made with a Brookfield viscometer

(14) (5) Elongation of the Resin after Curing a Silicone Composition

(15) Measurements are made in accordance with JIS K 6249

(16) (6) Measurements with an SPM

(17) 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.

(18) (Conditions under which samples are prepared)

(19) Ultramicrotome ULTRACUT N (trade name, manufactured by Reichert)

(20) Cryo unit FC 4E (trade name, manufactured by Reichert)

(21) Setting temperature: 130 C. for a sample; 130 C. for a glass knife

(22) Next, a cross section of the base fabric is measured with an SPM (Scanning Probe Microscope).

(23) Measurement apparatus: Nano Scope IV D3100 (trade name, manufactured by Digital Instruments)

(24) Measurement mode: Tapping mode/resonance frequency of 276.6 kHz

(25) Probe: NCH type silicone single crystal probe

(26) (Conditions under which measurements are made)

(27) Scan angle: 0

(28) Scan rate: 0.3 Hz

(29) Digital resolution (Number of sampling): 256256

(30) Control of amplitude level (Target amplitude): 1.6 V

(31) Amplitude decrement: 31.25%

(32) Integral gain: 0.65

(33) Proportional gain: 1.5

(34) 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.

(35) Furthermore, the form of a similar cross-sectional sample is observed with an SEM.

(36) FE-SEM S-4700 (trade name, manufactured by Hitachi, Ltd.

(37) Acceleration voltage: 1 to 5 kV

(38) Working distance: 12 to 13 mm

(39) (7) Compactness (Storability)

(40) 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 mm50 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.

(41) (8) Internal Pressure Retention (Deployability), Maximum Pressure Reaching Time (Deployability)

(42) 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.

(43) 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.

(44) (9) Scrub Test

(45) Measurements are made in accordance with ISO 5981.

(46) The dimensions of the sample are 50 mm W (warp yarn direction)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.

(47) 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.

(48) 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.

(49) (10) Wet Heat Aging

(50) A hollow weave fabric for an air bag after coating was treated at 80 C. and 95% RH for 200 hr.

(51) (11) Cooling-Heating Cycle Aging

(52) A hollow weave fabric for an air bag after coating was treated for 30 cycles under the following conditions A to C: A) the fabric is treated at 125 C. for 336 hr, and cooled at a rate of 2 C./min; B) the fabric is treated at 40 C. for 24 hr, and heated at a rate of 2 C./min; and C) the fabric is treated at 85 C. and 95% RH for 24 hr, and heated at a rate of 2 C./min.

Example 1

(53) 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.

(54) 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 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 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.

(55) 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.

(56) The liquid silicone composition used herein was produced as explained below.

(57) (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 mPa.Math.s at 25 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.

(58) (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 mPa.Math.s at 25 C. were mixed with a kneader. A hydrogen siloxane in an amount of 8 parts by weight having a viscosity of about 1,000 mPa.Math.s at 25 C. was further added to the mixture with stirring.

(59) 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 SiH bond and having a viscosity of about 20 mPa.Math.s at 25 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

(60) 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 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 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.

(61) 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.

(62) The liquid silicone composition used herein was produced as explained below.

(63) (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 mPa.Math.s at 25 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.

(64) (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 mPa.Math.s at 25 C. were mixed with a kneader. A hydrogen siloxane in an amount of 8 parts by weight having a viscosity of about 1,000 mPa.Math.s at 25 C. was further added to the mixture with stirring.

(65) 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 SiH bond and having a viscosity of about 20 mPa.Math.s at 25 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

(66) 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 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 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.

(67) 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.

(68) The liquid silicone composition used herein was produced as explained below.

(69) (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 mPa.Math.s at 25 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.

(70) (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 mPa.Math.s at 25 C. were mixed with a kneader. A hydrogen siloxane in an amount of 8 parts by weight having a viscosity of about 1,000 mPa.Math.s at 25 C. was further added to the mixture with stirring.

(71) 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 mPa.Math.s at 25 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

(72) 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 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 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.

(73) 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.

(74) In addition, the same liquid silicone composition as in Example 1 was used herein.

Example 3

(75) 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.

(76) 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 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 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.

(77) 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.

(78) In addition, the same liquid composition as in Example 1 was used.

Example 4

(79) 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.

(80) 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 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 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.

(81) 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.

(82) In addition, the same liquid silicone composition as in Example 1 was used herein.

Comparative Example 3

(83) 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.

(84) 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 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 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.

(85) 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.

(86) In addition, the same liquid silicone composition as in Example 1 was used herein.

Example 5

(87) 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.

(88) 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 C. for 1 minute in a drying machine.

(89) The liquid silicone composition used herein was produced as explained below.

(90) (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 mPa.Math.s at 25 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.

(91) (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 mPa.Math.s at 25 C. were mixed with a kneader. An organopolysiloxane in an amount of 8 parts by weight containing a SiH bond and having a viscosity of about 1,000 mPa.Math.s at 25 C. was further added to the mixture with stirring.

(92) 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 SiH bond and having a viscosity of about 20 mPa.Math.s at 25 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.

(93) 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 C. for 2 minutes in a drying machine.

(94) The liquid silicone composition used herein was produced as explained below.

(95) (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 mPa.Math.s at 25 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.

(96) (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 mPa.Math.s at 25 C. were mixed with a kneader. An organopolysiloxane in an amount of 8 parts by weight containing a SiH bond and having a viscosity of about 1,000 mPa.Math.s at 25 C. was further added to the mixture with stirring.

(97) 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 SiH bond and having a viscosity of about 20 mPa.Math.s at 25 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.

(98) 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.

(99) 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

(100) 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.

(101) 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.

(102) 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

(103) 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.

(104) 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.

(105) 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

(106) 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.

(107) 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.

(108) 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.

(109) 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

(110) 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.

(111) 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.

(112) 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

(113) 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.

(114) 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.

(115) 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

(116) 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.

(117) 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 C. for 1 minute in a drying machine.

(118) The liquid silicone composition used herein was produced as explained below.

(119) (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 mPa.Math.s at 25 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.

(120) (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 mPa.Math.s at 25 C. were mixed with a kneader. An organopolysiloxane in an amount of 8 parts by weight containing a SiH bond and having a viscosity of about 1,000 mPa.Math.s at 25 C. was further added to the mixture with stirring.

(121) 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 mPa.Math.s at 25 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.

(122) 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 C. for 2 minutes in a drying machine.

(123) The liquid silicone composition used herein was produced as explained below.

(124) (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 mPa.Math.s at 25 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.

(125) (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 mPa.Math.s at 25 C. were mixed with a kneader. An organopolysiloxane in an amount of 8 parts by weight containing a SiH bond and having a viscosity of about 1,000 mPa.Math.s at 25 C. was further added to the mixture with stirring.

(126) 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 mPa.Math.s at 25 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.

(127) 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.

(128) 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.

(129) 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.

(130) Moreover, Table 3 also shows the results of SPM measurements in Examples 10 to 11 and Comparative Example 6 explained below.

Example 10

(131) 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

(132) 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

(133) 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

(134) 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.

(135) 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

(136) 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.

(137) 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

(138) 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.

(139) 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 C. for 1 minute in a drying machine.

(140) The liquid silicone composition used herein was produced as explained below.

(141) (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 mPa.Math.s at 25 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.

(142) (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 mPa.Math.s at 25 C. were mixed with a kneader. An organopolysiloxane in an amount of 8 parts by weight containing a SiH bond and having a viscosity of about 1,000 mPa.Math.s at 25 C. was further added to the mixture with stirring.

(143) 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 SiH bond and having a viscosity of about 20 mPa.Math.s at 25 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.

(144) 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 C. for 2 minutes in a drying machine.

(145) The liquid silicone composition used herein was produced as explained below.

(146) (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 mPa.Math.s at 25 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.

(147) (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 mPa.Math.s at 25 C. were mixed with a kneader. A hydrogen siloxane in an amount of 8 parts by weight having a viscosity of about 1,000 mPa.Math.s at 25 C. was further added to the mixture with stirring.

(148) 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 SiH bond and having a viscosity of about 20 mPa.Math.s at 25 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.

(149) 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.

(150) 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

(151) 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.

(152) 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

(153) 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

(154) 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

(155) 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

(156) 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

(157) 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.

(158) 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 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.

(159) The silicone composition used for the third layer was produced as explained below.

(160) (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 mPa.Math.s at 25 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.

(161) (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 mPa.Math.s at 25 C. were mixed with a kneader. An organopolysiloxane in an amount of 8 parts by weight containing a SiH bond and having a viscosity of about 1,000 mPa.Math.s at 25 C. was further added to the mixture with stirring.

(162) 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 mPa.Math.s at 25 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.

(163) 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

(164) 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.

(165) 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.

(166) 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

(167) 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.

(168) 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 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 C. for 2 minutes in a drying machine.

(169) 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 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.

(170) 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.

(171) 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.

(172) 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.

(173) 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.

(174) TABLE-US-00002 TABLE 2 C. C. Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 4 Ex. 5 Total size of 175 235 350 470 110 700 warp yarn (dtex) Total size of 175 235 350 470 110 700 weft yarn (dtex) Warp yarn 83 72 60 51 110 38 density (ends/ 2.54 cm) Weft yarn 83 72 60 51 110 38 density (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 53 57 60 62 46 72 (mm) Internal 91 93 93 95 Burst 93 pressure retention (average (%)) Internal 89-96 91-95 92-95 93-97 Burst 92-95 pressure retention (min.-max. (%))

(175) 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 ( of first 1.21 1.32 1.60 1.09 layer)/( 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 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.

(176) 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.

(177) 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

(178) 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.