This sample is double-sided coated with adhesive and used for protecting the back panel of mobile phone screens. During testing, remove the sample and peel off the protective film
One end, the adhesive surface is tested downwards. Several types of membranes include imported membranes and domestically produced membranes, both of which are known to have surface coatings
There are slight differences in the adhesive, try using infrared spectroscopy for identification and classification.