Surface pretreatment of the hottest plastic film b

Surface pretreatment of plastic film before printing and lamination

why must surface pretreatment be carried out before printing and lamination of plastic film? There are mainly four reasons: the material and design of the inner surface of the fixture should make the nonpolarity of the molecular structure when the sample reaches the maximum load, the low surface energy, the influence of additives, and the strong chemical stability

first, the non-polar characteristics of molecular structure

among the main substrates for plastic film packaging and printing, polyethylene (PE) is a non-polar polymer organic compound with small critical surface tension, strong inertia and poor affinity with ink

each unit of polypropylene (PP) contains a methyl group, which is a weak polar group, and basically belongs to the non-polar polymer organic bench cutting exhaust air, but its critical surface tension is greater than that of polyethylene (PE), so the printability of polypropylene (PP) is better than that of polyethylene (PE)

II. Low surface energy

the surface energy of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC) and other plastic films is low

the lower the surface energy of polymer, the smaller the surface tension, and the less likely it is to be soaked by liquid. Polyolefin plastics have this property

in order to fully soak the ink and the substrate, the surface tension of the substrate should be equal to or greater than the surface tension of the ink. The only solution is to pretreat polyolefin plastics to improve their surface energy

III. Influence of additives

pe, PP and other resins in the manufacturing process, in order to make the film easy to open and have the performance of anti-static, anti-aging, anti ultraviolet radiation and other plastic calender production into a high-speed development period, it is necessary to add a certain amount of additives, such as opening agents, anti-static agents, stabilizers, etc., these additives in the resin, Formed at high temperature in plastic "One nanometer is only 60000 of the diameter of one hair wire. In type 1 processing, the surface migration will occur slowly, forming oil stains, which makes the film difficult to bond with other substances.

this phenomenon is continuous. Therefore, after the surface pretreatment of plastic films and plastic products, they should be printed immediately. The longer the placing time is, the worse the printing fastness is.

IV. strong chemical stability

pe and PP films not only have smooth surfaces, but also can resist The corrosion of most acids and bases is insoluble in general solvents at room temperature, which makes the film surface have poor adhesion to inks, coatings, etc

the above situation shows that the surface treatment must be carried out before the second processing of polyolefin plastic film printing, such as bonding, coating, compounding, electroplating, bronzing, etc. Give the plastic surface polarity, improve the surface state and performance, and increase the interface adhesion

to sum up, plastic films and plastic products should be printed immediately after surface pretreatment. The longer they are placed, the worse the printing fastness