How to do screen printing on PE and PP?

How is screen printing done on PE and PP? Screen printing on PE and PP is not simply about transferring paint to the plastic surface. Due to the low surface energy of polyethylene and polypropylene surfaces, the production additives used, and mold release residues, the paint may not sufficiently wet the surface. As a result, even if the print looks smooth at first, it may peel off during the tape test, be wiped off by friction, or the product may be damaged […]