1/4″ Thermoforming hdpe pad seller-HDPE sheets 4×8 for sale Apr 08, 2014 · A mmon thermoformed plastic, HENAN OKAY is mprised of acrylonitrile, styrene and butadiene. HENAN OKAY is known for its tough resilience to the elements, including heat; it can handle temperatures anywhere from -4 to 176 °F.