PE (polyethylene) has long been regarded as a "tough nut" in the plastic coating field due to its molecular characteristics such as low surface energy and strong non-polarity. The latest technical analysis from Zhangdao Chemical indicates that the adhesion of PE coatings is difficult to solve thoroughly, long-term and stably. The core crux lies in the material's nature of lacking reactive functional groups, having a dense surface and being not easily swollen.
    Currently, feasible industrial solutions focus on three pathways: improving surface energy through flame, corona or plasma treatment to create a short "paintable window", with coating required within 4-8 hours after treatment; using bridging special primers such as chlorinated polyolefin (CPO) to achieve adhesion through molecular chain entanglement; or abandoning traditional coating thinking and adopting alternative schemes like co-extrusion coloring and in-mold decoration. Experts warn that methods such as directly using strong solvent coatings and superimposing multiple surface treatments are basically ineffective, and cross-hatch testing cannot guarantee long-term stability.
    PE coating is only worth trying when low-crystallinity PE material is selected, coating time is strictly controlled, special primers are used, and durability requirements are relatively low. The industry calls on enterprises to choose schemes based on material characteristics and avoid blind formula testing.

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