Analysis of PET film quality:
A: The color is yellowed or grayed out
PET film, especially after the roll into the axis of view, the phenomenon of yellowing or gray hair with the naked eye can see. And there are yellow bars, you must start the film, or light observation. Or shop on a white liner above, in order to better identify.
Gel point, yellow dot, black spots "for the same reason, yellowing is poor thermal stability of the resin, or a greater amount of air into the extruder's sake. When the resin in the thermal oxidation produces greater acetaldehyde. The antimony trioxide is reduced to antimony, causing the film (resin) to be grayed out. The presence of yellow bars is mostly in the replacement of the filter, or after the replacement of the resin. The reason is that at the time of replacement, There are some resin in the machine to stay too long, so that part of the resin yellow, and these yellow after the formation of resin is no longer possible with the normal melt plasticization of the full mixing evenly, so there are yellow bars appear.
Two: static too large
A feature of electrostatic phenomena is adsorption. The PET film surface friction, or film roll unwinding of the peel, or film at high speed operation, will form a good power. If there is dust, scraps of paper, hair, etc. in the vicinity of the film, it may be adsorbed and affect the quality of the product film (especially the capacitive film), and it may cause accidents such as fire and electricity when the static electricity is serious. The static electricity of the film is too large and has a bad effect on the subsequent processing and processing. For example, the electrostatic size of the adhesive PET film can be about 500v, and the static size of the film is different.
PET film is a polarity of the electrical insulation material, which makes the friction, shear and other effects of the charge can not be passed away, and in its surface accumulation of static electricity. The electrostatic size of PET film and the electrical properties of resin body. As well as film-making process. Because they directly affect the structure and properties of the surface / surface of the film, such as the crystallinity of the surface layer, the number of polar groups and their orientation, the size of the contact surface of the two films affect the formation of static electricity. According to this, can also explain the two films Why is the static electricity.