China's Environmental Protection Ministry on January 9, 2009, allowed the construction in Gulei of a two-plant chemical project : a Tenglong (腾龙)(DAC - Dragon Aromatics Co.) company factory to produce p- (meaning para-) xylene, and a Xianglu (翔鹭) company factory to use said p-xylene to produce Polyethylene terephthalate.
Parylene development started in 1947, when Michael Szwarc discovered the polymer as one of the thermal decomposition products of a common solvent p-xylene at a temperatures exceeding 1000 °C.