Poly thread is either spun, filament, or trilobal. Spun is the weaker of the two and used for serger thread as three or more cones are used at one time.
Explanation of poly thread:
https://www.superiorthreads.com/educ...lyester-thread
We don't recommend spun polyester for quilting, as it is not as strong as corespun, filament, or trilobal polyester threads.