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LDPE Specific Gravity (Density)

2026-02-05 10:43:14 Injection Molding

LDPE (Low-Density Polyethylene) is produced via high-pressure free radical polymerization, featuring highly branched molecular chains and low crystallinity. It offers excellent flexibility, transparency, and processability, with the lowest density among polyethylenes. It is a traditional core material for films, hoses, coatings, and soft injection-molded products. LDPE density is primarily affected by polymerization pressure and branching degree. Virgin material density has an extremely narrow range, with a slight increase after filling modification. Accurate density is fundamental for soft product design and processing.

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  • Virgin LDPE: 0.910–0.915 g/cm³, typical value 0.912 g/cm³. It offers good transparency, flexibility, and processability with very low density, suitable for food packaging films, shopping bags, hoses, and coatings.

  • High-Flow LDPE: 0.912–0.917 g/cm³. Reduced molecular weight improves flowability with slightly higher density, suitable for thin-walled injection-molded products and precision coatings.

  • Toughened Modified LDPE: 0.908–0.914 g/cm³. Elastomer modification slightly reduces density, enhancing low-temperature toughness for frozen food packaging and cold-resistant hoses.

  • Filled Modified LDPE: 0.915–0.940 g/cm³. Inorganic fillers increase density, reducing costs and improving stiffness for low-end packaging films and injection-molded miscellaneous parts.

Density parameters are the core basis for designing flexible films, hoses, and coating products. Its extremely low density meets lightweight flexibility requirements, and a stable density range ensures uniformity in blown film and extrusion processes. Density calculations directly influence raw material ratios, process temperature settings, and product weight cost management, while supporting its core properties of flexibility, transparency, and ease of processing.

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