Vehicle safety devices, seam tapes for use in airbag and related methods

Abstract

Vehicle safety devices and seam tapes for use in safety airbags along with their methods of formation and use are provided. The vehicle safety device can comprise an airbag and a pyrotechnic device positioned within working proximity to an aperture defined in the airbag and configured to fill the interior space of the airbag with a gas upon ignition. The vehicle safety device can also comprise a seam tape positioned over the seam joining a first fabric section and a second fabric section of the airbag. The seam tape can be configured to melt enough to flow into the needle puncture holes formed along the seam upon ignition of the pyrotechnic device.

What is claimed is: 
     
         1 . A vehicle safety device, comprising:
 an airbag forming an interior surface and an interior space and defining an aperture, the airbag comprising a first fabric section and a second fabric section, wherein the first fabric section is joined along a seam to the second fabric section;   a pyrotechnic device positioned within working proximity to the aperture defined in the airbag, wherein the pyrotechnic device is configured to fill the interior space of the airbag with a gas upon ignition; and   a needlepunched nonwoven seam tape secured on the interior surface of the airbag over the seam of the airbag, the needlepunched nonwoven seam tape comprising a first side that is calendered and a second side that is not calendered.   
     
     
         2 . The vehicle safety device according to  claim 1 , wherein the seam tape comprises at least one polymer and being configured to melt upon exposure to the heat from the gas generated by the pyrotechnic device such that the melted polymer of the seam tape flows into and occupies the needle puncture holes to reduce leakage of the gas through the needle puncture holes.. 
     
     
         3 . The vehicle safety device according to  claim 1 , wherein the needlepunched nonwoven material of the seam tape is calendered using a S-type calender machine so that the first side of the needlepunched nonwoven material of the seam tape has different surface bonding and finishing profile than the second side of the needlepunched nonwoven material of the seam tape. 
     
     
         4 . The vehicle safety device according to  claim 1 , wherein the seam tape comprises a needlepunched nonwoven material of thermoplastic polymer fibers comprising a denier of between about 2 and about 15. 
     
     
         5 . The vehicle safety device according to  claim 1 , wherein the seam tape comprises a needlepunched nonwoven material of thermoplastic polymer fibers comprising a denier of between about 2 and about 5. 
     
     
         6 . The vehicle safety device according to  claim 1 , wherein the polymer fibers comprise about 100% polyester. 
     
     
         7 . The vehicle safety device according to  claim 1 , wherein the polymer fibers comprise about 80% polyester and about 20% polypropylene. 
     
     
         8 . A seam tape for securing along seams of an airbag cushion used in a vehicle safety device, the seam tape comprising:
 a needlepunched nonwoven material comprising a first side that is calendered using a S-type calender machine and a second side that is not calendered such that the first side of the needlepunched nonwoven material of the seam tape has different surface bonding and finishing profile than the second side of the needlepunched nonwoven material of the seam tape; and   the needlepunched nonwoven material comprising thermoplastic polymer fibers comprising a denier of between about 2 and about 15 with at least one set of the polymer fibers that is configured to melt upon exposure to heat from a gas generated by a pyrotechnic device in an airbag such that the melted polymer of the polymer fibers of the a needlepunched nonwoven material flows into and occupies needle puncture holes to reduce leakage of the gas through the needle puncture holes.   
     
     
         9 . The seam tape for an airbag cushion according to  claim 8 , wherein the thermoplastic polymer fibers of the needlepunched nonwoven material of comprising a denier of between about 2 and about 5. 
     
     
         10 . The seam tape for an airbag cushion according to  claim 8 , wherein the thermoplastic polymer fibers comprise about 100% polyester. 
     
     
         11 . The seam tape for an airbag cushion according to  claim 8 , wherein the thermoplastic polymer fibers comprise about 80% polyester and about 20% polypropylene. 
     
     
         12 . The seam tape for an airbag cushion according to  claim 8 , wherein the thermoplastic polymer fibers comprise staple fibers having a length of about 1½ inches to about 6 inches. 
     
     
         13 . The seam tape for an airbag cushion according to  claim 8 , wherein the polymer fibers comprise staple fibers having a length of a length of about 2 inches to about 5 inches. 
     
     
         14 . The seam tape for an airbag cushion according to  claim 8 , wherein the polymer fibers comprise staple fibers having a length of about 2½ inches to about 4 inches. 
     
     
         15 . The seam tape for an airbag cushion according to  claim 8 , wherein the polymer fibers are crimped. 
     
     
         16 . The seam tape for an airbag cushion according to  claim 8 , wherein the type of polymer fibers used in the seam tape, the fibers' denier and length, and a thickness of the seam tape is dependent on a velocity and temperature of inflation gas provided by a pyrotechnic device used in a vehicle safety device. 
     
     
         17 . The seam tape for an airbag cushion according to  claim 8 , wherein the polymer fibers comprise crimped small denier and short staple length fibers to increase integrity of the nonwoven material while also increasing the absorption of an impingent shock wave and the melting and liquification of the polymer fibers due to a velocity and temperature of inflation gas provided by a pyrotechnic device used in a vehicle safety device. 
     
     
         18 . The seam tape for an airbag cushion according to  claim 8 , wherein the polymer fibers should also be of a composition and size that they melt before a fabric of an airbag cushion.