Polyamide-46 multifilament and sewing thread for airbag

Abstract

A purpose of the present invention is to provide a polyamide-46 multifilament that has high strength, high-temperature dimensional stability, and excellent stretchability, which have not been attained with any conventional technique, and that is hence suitable for use as a sewing thread for airbags having mechanical properties which can inhibit the sewed portions from suffering an air leakage of a high-temperature high-power gas. The polyamide-46 multifilament has the following physical properties (1) to (3). (1) A strength of 6.0-9.0 cN/dtex and an elongation of 15-30%. (2) A degree of elongation E10 (100° C.), as measured after stretching 10 times in a 100° C. environment, of less than 1.0%. (3) A difference between the elongation under a load of 2.0 cN/dtex at ordinary temperature and the elongation under a load of 2.0 cN/dtex in a 100° C. environment of less than 0.5%.

1 . A polyamide-46 multifilament comprising the following physical properties (1) to (3):
 (1) a strength of 6.0-9.0 cN/dtex and an elongation of 15-30%;   (2) E10(100° C.)<1.0% wherein E10(100° C.) is a degree of elongation after stretching 10 times in an environment of 100° C.; and   (3) M (100° C.)−M (R.T.)<0.5% wherein M (R.T.) is an elongation under a load of 2.0 cN/dtex and ordinary temperature, and M (100° C.) is an elongation under a load of 2.0 cN/dtex and an environment of 100° C.   
     
     
         2 . The polyamide-46 multifilament according to  claim 1 , comprising the following physical properties (4) and (5);
 (4) E10′ (R.T.)−E10(R.T.)≤0% wherein E10(R.T.) is a degree of elongation after stretching 10 times under ordinary temperature, and E10′ (R.T.) is a degree of elongation after stretching 10 times under ordinary temperature after heat treatment at 120° C. for 24 hours; and   (5) M′ (R.T.)−M (R.T.)≤0% wherein M (R.T.) is an elongation under a load of 2.0 cN/dtex and ordinary temperature, and M′ (R.T.) is an elongation under a load of 2.0 cN/dtex and ordinary temperature after heat treatment at 120° C. for 24 hours.   
     
     
         3 . The polyamide-46 multifilament according to  claim 1 , having a total fineness of 300-2300 dtex and a single filament fineness of 2-20 dtex. 
     
     
         4 . The polyamide-46 multifilament according to  claim 1 , wherein sulfuric acid relative viscosity ηr is 3.0<ηr<4.5. 
     
     
         5 . A sewing thread for airbags, comprising the polyamide-46 multifilament according to  claim 1 .