Special film to identify the basic method

In PP, PE reworked material, the manufacturer will encounter many difficult to solve the problem, that today we have to give you an example. As we all know, part of reworked material are imported from abroad, such as Japan, the United States, South Korea, etc. Have a kind of PP, PE film, it is difficult to identify to the naked eye, light the film transparency and smoothness are good, but to get on the bus to the extruding machine, there will be a small number of black spots after doing, in the process of the temperature control is also appropriate, and there are no other impurities mixed in, why can appear such black spots? Reason is that the film at the time of production for packing, coated with a uv coating, the coating temperature at 120 degrees to decompose, the plasticizing, 150-160 degrees after the coating film coking is grey, is a black dot above. This results in the decrease of the film in terms of price, bring loss to production. So some manufacturer at the time of purchase must pay attention to this kind of PP, PE film, so as to avoid unnecessary losses.