Generally injection molding PP, POM and other polymers are screen printing. Screen printing is the same as screen printing, and the principle is also similar. That is, the basic principle of screen mesh printing is used to permeate ink, and non-graphic printing is not permeable to ink. During printing, pour ink on one end of the screen printing plate, apply a certain pressure on the ink portion of the screen printing plate with a scraper, and move toward the other end of the screen printing plate. The ink is squeezed by the scraper from the mesh in the graphic part to the substrate while moving. It is true that in practical applications, phenolic, alkyd and other types of inks or coatings are easy to operate, but their adhesion, hardness and wear resistance are difficult to meet the requirements. Your letter does not state what type of ink the polymer uses. So I can only suggest that you use acrylic, nitro, polyurethane or epoxy type inks or coatings to improve the adhesion. PP and POM are high-crystallinity, low-surface tension, non-polar molecular structure polymer materials. In their molecular structure, there are no polar groups such as carbonyl, carboxyl, hydroxyl, etc., so it is more suitable for network Printing. But for polyolefin materials, in order to ensure the adhesion of the ink film, the plastic surface must be treated. In general, there are two popular methods at present: One method is to increase the surface tension of plastic solids. The method is to use ultraviolet rays to increase the molecular weight of the low molecular layer on the plastic surface in the presence of photosensitizer and increase the surface tension of the solid surface. . Another method is to oxidize polyolefin plastic surface molecules to generate some polar groups such as carboxyl groups, hydroxyl groups, and carbonyl groups on the surface to increase the critical surface tension of the plastic surface and improve the adhesion of inks and coatings to the plastic surface Performance, flame, chromic acid mixture, discharge oxidation, ozone oxidation and other treatment methods can be used. This step is very necessary and cannot be cancelled in theory. The use of PP treatment water treatment process is too complicated, you can consider using other methods to replace, but this step of surface treatment is very necessary. Household Cleaning Products And Accessories Household Cleaning Products And Accessories,Cleaning Cloth,Oil Removal Dishwashing Cloth,Thickened Suction Kitchen Artifact Huayao Master (Puyang) Automation Equipment Co., Ltd. , https://www.huayaomaster.com