Kevlar thread is more than double in strength as polyester or nylon threads. Kevlar thread has little to no stretch which helps hold a very tight seam. Kevlar thread does not melt, instead, Kevlar thread decomposes around 800 degrees Fahrenheit (or 426 degrees Celcius).
Kevlar thread is used in applications where high-heat resistance is needed and where strength is an added plus. Some applications of Kevlar thread are fire suits, racing gear, tactical gear, ballistic applications, marine uses and much more.