Preparation process of PET (Polyethylene Terephthalate) film

The invention discloses a preparation process of a PET film, and relates to the field of moisture permeability detection.The detection device comprises a base, the base is provided with a first clamping rod and a second clamping rod in a spaced mode, the first clamping rod and the second clamping rod are each composed of a fixing block and two clamping blocks, the base is provided with a mounting plate in the vertical direction, and the fixing blocks are arranged on the mounting plate. The fixing block of the first clamping rod is rotationally connected to the mounting plate, the fixing block of the second clamping plate is fixedly mounted on the mounting plate, the two clamping blocks are integrally formed on the corresponding fixing blocks, and a clamping groove is formed between the two clamping blocks; the opposite sides of the two clamping blocks are rotationally connected with pre-tightening plates, in the initial state, the pre-tightening plates are obliquely arranged, the pre-tightening plates incline