The core objective of wax selection is to simultaneously meet four requirements: lubrication balance, foaming stability, surface gloss, and non-blooming. In terms of viscosity selection, high-viscosity polyethylene wax offers superior gloss and higher molecular weight with low bloom tendency despite slightly poorer dispersion, making it suitable for products with hazy surfaces that require brightness enhancement. Low-viscosity wax provides good dispersion but is prone to migration and blooming, making it only suitable for formulations with high dispersion requirements. The recommended wax types in order of preference are: high-density polyethylene wax for high-temperature processing, oxidized polyethylene wax for balanced internal and external lubrication with low bloom tendency, Fischer-Tropsch wax for its narrow molecular weight distribution and excellent foaming stability, while cracked wax is not recommended for high-gloss products due to significant quality fluctuations. Key selection pitfalls to avoid include choosing a melting point of 100–140°C, particle size of 5–20μm, and controlling the addition amount at 0.1–0.4 phr. Pure polyethylene wax must be used, avoiding recycled wax or inferior cracked wax that can cause surface stains and dullness.
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