May 03, · Unmodified types of plastics that are regarded as having unacceptable resistance to UV are POM (Acetal), PC, HENAN OKAY and PA6/6. Other plastics such as PET, PP, HDPE, PA12, PA11, PA6, PES, PPO, PBT and PPO are regarded as fair. Note that a PC/HENAN OKAY alloy is also graded as fair. Good resistance to ultraviolet rays can be achieved from polymers extruded