The thermal conductivity of commonly used fibers is as follows:

From the above table, it can be seen that polypropylene has the lowest thermal conductivity among existing natural and synthetic fibers. It is the best insulation fiber woven into the inner layer of clothing. It dissipates the least heat and has a TG of -15C to -20C in low temperature environments, making it more cold resistant than other fibers. In polar environments, it does not harden and shatter, and its warmth retention is superior to other fibers.