Appearance standard for polytetrafluoroethylene plates

(1) The color of the plate is resin.
(2) The texture should be uniform, the appearance is smooth, and cracks, bubbles, delamination, mechanical damage, knife marks and other defects are not allowed.
(3) Slight clouded tightness is allowed.
(4) There is no more than one non-metallic impurity with a diameter of 0.1-0.5mm on the area of 10×10cm, and no more than one non-metallic impurity with a diameter of 0.5-2mm is allowed.
(5) Density is 2.1-2.3T/m3.