Air-bag-use non-coat base cloth and air-bag-use fiber

Abstract

A base fabric for non-coated air bags, in which both the warp and the weft or either of them comprise synthetic fiber multifilaments of flattened cross-section monofilaments having a degree of flatness of from 1.5 to 8.0 and having a monofilament fineness of at moat 10 dtex and a total fineness of from 200 to 1000 dtex, and which satisfies all the following (1) to (3): (1) its cover factor falls between 1700 and 2200; (2) its air permeability under low pressure, P L , is at most 0.1 cc/cm 2 /sec; and (3) its air permeability under high pressure, P H , is at most 20 cc/cm 2 /sec, has high tenacity and low air permeability necessary for air bags and is compactly foldable to save the housing space for it.

1 . A base fabric for non-coated air bags in which both the warp and the weft or either of them comprise synthetic fiber multifilaments of flattened cross-section monofilaments having a degree of flatness of from 1.5 to 8.0 and having a monofilament fineness of at moat 10 dtex and a total fineness of from 200 to 1000 dtex, and which satisfies all the following (1) to (3): 
 (1) its cover factor falls between 1700 and 2200;    (2) its air permeability under low pressure, P L , is at most 0.1 cc/cm 2 /sec; and    (3) its air permeability under high pressure, P H , is at most 20 cc/cm 2 /sec.    
     
     
         2 . The base fabric for non-coated air bags as claimed in  claim 1 , of which the air permeability under high pressure after stretched, P S , is at most 50 20 cc/cm 2 /sec.  
     
     
         3 . The base fabric for non-coated air bags as claimed in  claim 1  or  2 , wherein the horizontal index, HI, of the synthetic fiber multifilaments is at least 0.75 in terms of the cosine of the angle at which the horizontal direction of the base fabric crosses the direction of the major axis of the cross section of each monofilament.  
     
     
         4 . The base fabric for non-coated air bags as claimed in any one of  claims 1  to  3 , which is such that the number of residual entanglements in the warp drawn out of the base fabric is at most 10/m.  
     
     
         5 . The base fabric for non-coated air bags as claimed in any one of  claims 1  to  4 , of which the residual oil content is at most 0.1 % by weight.  
     
     
         6 . The base fabric for non-coated air bags as claimed in any one of  claims 1  to  5 , wherein the synthetic fiber multifilaments are of a polyamide having a viscosity relative to sulfuric acid of at least 3.0.  
     
     
         7 . Fibers for air bags, which comprise synthetic fiber multifilaments and satisfy all the following (4) to (7): 
 (4) the degree of flatness of each monofilament, which is indicated by the ratio of the length, a, of the largest major axis to the length, b, of the largest minor axis, a/b, of the cross section of the monofilament, falls between 1.5 and 8.0;    (5) the degree of surface smoothness of each monofilament in the direction of the major axis of the cross section, which is indicated by the ratio of the length, c, of the smallest minor axis to the length, b, of the largest minor axis, c/b, is at least 0.8;    (6) the monofilament fineness is at most 10 dtex; and    (7) the length, b, of the largest minor axis is at most 15 μm.    
     
     
         8 . The fibers for air bags as claimed in  claim 7 , in which the number of residual entanglements after stretched under tension is at most 15/m.  
     
     
         9 . The fibers for air bags as claimed in  claim 7  or  8 , of which the synthetic fiber multifilaments are of a polyamide having a viscosity relative to sulfuric acid of at least 3.0.  
     
     
         10 . The base fabric for non-coated air bags as claimed in any one of  claims 1  to  6 , which comprises the fibers of any of  claims 7  to  9 .