Nylon Used to be the most popular material to create seat belts. However, it stretches easily. It is also more prone to wear and tear. Since tiny abrasions and damage can significantly make seat belts less effective, the seat belt material used today is replaced with polyester. This final rule http://pandora.nla.gov.au/external.html?link=https://www.ledteks.com/seatbelt-and-safety-belt-webbing