There are many kinds of Shrink Film, one is PVC, this shrink film is blown, is generally out of the coil. PVC film is currently the most widely used film material. It is cheap, temperature shrinkage range is big, the heat source requirements are not high. The main processing heat source is hot air, infrared or a combination of the two. But PVC is difficult to recover, burning gas, is not conductive to environmental protection, it has been banned in European, Japan. Acceptance standard according to transparency, gloss, whether the film is a node or not, it the membrane uniform?
The second is POF Shrink Film, this kind film is made of pressure rock, generally out of the bag, if the tube material, then order to be more than a few tons. Regular color is transparent. It can be printed on request. Finished products are mainly used in medicine, cosmetics, disinfection tableware and other packaging. Acceptance level: is it open when contraction? Is the printing fade? And check the transparency.
The third film is PE, it mainly used in heavy objects, optical cable, pipe, Coke package. Out of the majority of the tube material.