| abstract |
A fabric for use in forming an air bag which is smooth in initial expansion when it is inflated, has high bursting strength and is superior in safety comprising all the following characteristics: (A) the load-elongation curve at least in either of warp and weft directions of the fabric is in a substantially upwardly convex form when its elongation ε is within a range, 1 % ≤ ε ≤ 20 %; (B) when the elongation ε of the fabric is within a range, ε ≤ 10 %, the tensile strength S(ε) of the fabric is 10∩100 kg/3 cm both in the warp and weft directions; and (C) the tensile toughness of the fabric which is defined as below is 2,000∩4,000 kg.%/3 cm both in the warp and weft directions (where in a graph showing load-elongation curves of the fabric prepared, respectively, for the warp and weft directions, the above tensile toughness represents the area of a region defined by the load-elongation curve and the horizontal axis when the load is nil), wherein this fabric for an air bag is made by a method comprising the steps of using as warps and wefts polyester base filaments having a tensile break elongation of 9∩18 % and a dry heating shrinkage factor of 3∩13 % at 150 °C without being twisted so as to prepare raw fabric whose tensile strength both in the warp and weft directions is more than 1,000 kg.%/3 cm but less than 2,000 kg.%/3 cm, providing shrink-set treatment to the raw fabric or fabric made by refining the raw fabric and controlling this shrink-set treatment such that both the warp and weft density increase factors of the raw fabric or the fabric fall within a range of 5 to 25 % and the elongation increase factor of the fabric both in the warp and weft directions at the tensile break elongation of the polyester raw filaments fall within a range of 70∩250 %. |