Gastight woven fabric sheet for air bags and a process for producing same

A gastight woven fabric sheet for air bags, comprising a woven fabric formed from a plurality of warp and wefts each comprising a polyester multifilament yarn having a yarn thickness of 200 to 550 deniers and a twist multiplier of 3,000 or less, said woven fabric having a smoothed surface and an opposite non-smoothed surface thereof, and satisfying all the relationships (1) to (7):

• 78.74p.gtoreq.Q(p).gtoreq.7.874p (1)
• R1>R2 (2)
• R1>R3 (3)
• 3.5.gtoreq.R3.gtoreq.0.5 (4)
• Mu-Mc.gtoreq.0.0005 (5)
• Su-Sc.gtoreq.0.5 (6)
• and
• 85.gtoreq.P.gtoreq.70 (7)
• in which relationships (1) to (7),
• p represents a pressure in unit of kg/cm.sup.2 G and satisfying the relationship:
• 0.ltoreq.p.ltoreq.0.03;
• Q(p) represents a gas permeability function in units of ml/cm.sup.2 /sec of the woven fabric under the pressure p;
• R1 represents a radius of curvature in units of mm of a smoothed surface side half portion of a cross-sectional profile of at least one selected from the warp and weft yarns located in the smoothed surface portions of the woven fabric;
• R2 represents a radius of curvature in units of mm of an opposite side half portion of the cross-sectional profile of the at least one selected from the warp and weft yarns located in the smoothed surface portion of the woven fabric;
• R3 represents a radius of curvature in units of mm of a non-smoothed surface side half portion of a cross-sectional profile of at least one selected from the warp and weft yarns located in the non-smoothed surface portion of the woven fabric;
• Mc represents an average deviation in surface frictional coefficient of the smoothed surface of the woven fabric;
• Mu represents an average deviation in surface frictional coefficient of the non-smoothed surface of the woven fabric;
• Sc represents an average deviation in surface roughness in units of .mu.m of the smoothed surface of the woven fabric;
• Su represents an average deviation in surface roughness in units of .mu.m of the non-smoothed surface of the woven fabric;
• and
• P represents a fiber packing in units of % of the woven fabric.