PE-HD (High-Density Polyethylene): Applications, Advantages & Injection Molding Guide

PE-HD, or High-Density Polyethylene, is a versatile semi-crystalline thermoplastic known for its high strength-to-density ratio, chemical resistance, and durability. It is widely used in packaging, automotive, construction, and household applications.

What Is PE-HD?
PE-HD is produced through the polymerization of ethylene under low pressure with a catalyst, resulting in a linear polymer with minimal branching. This gives it a high crystallinity level and a dense, rigid structure. Compared to low-density polyethylene (PE-LD), PE-HD has better mechanical properties and greater resistance to heat and chemicals.

Key Applications of PE-HD
Packaging
– Milk jugs and detergent bottles
– Food containers and lids
– Crates, trays, and drums

Automotive
– Fuel tanks and reservoir bottles
– Protective underbody covers
– Battery casings and cable insulation

Construction & Infrastructure
– Water and gas distribution pipes
– Conduits and plastic lumber
– Geomembranes and roofing sheets

Consumer Goods
– Toys, furniture, and storage bins
– Cutting boards and kitchenware
– Outdoor equipment

Medical
– Disposable containers and tubing
– Sterile packaging
– Laboratory trays

Advantages of PE-HD
– High strength and stiffness
– Excellent resistance to chemicals and moisture
– Good impact resistance at low temperatures
– Lightweight and flexible
– Low water absorption
– UV-resistant grades available for outdoor use
– FDA-approved variants for food contact

Injection Molding Guidelines for PE-HD
1. Drying Requirements
PE-HD does not typically require drying before molding unless improperly stored.
– Drying: Generally not needed
– Optional drying: 60–70 °C for 1–2 hours if required

2. Melt and Mold Temperatures
– Melt temperature: 200–260 °C
– Mold temperature: 50–95 °C
– Higher mold temps enhance surface finish and dimensional stability

3. Injection Pressure & Speed
– Pressure: 700–1050 bar depending on part thickness
– Speed: High-speed injection recommended for thin-walled components

4. Runner and Gate Design
– Runner diameter: 4–7.5 mm
– Gate types: Suitable for all gate types (submarine, fan, edge)
– Gate length: Max 0.75 mm for efficient shearing
– Hot runner systems are well-suited for PE-HD

Common Molding Issues
– Warping: Use balanced mold cooling and consistent wall thickness
– Shrinkage: Typical range 1.5–4%; adjust for part design
– Stress cracking: Choose appropriate material grade with low MFR
– Sink marks: Optimize holding pressure and gate location

Final Thoughts
PE-HD offers outstanding value as a durable, chemically resistant, and easy-to-process material. Its mechanical robustness and flexibility make it ideal for applications across multiple industries. From fluid handling systems to household goods, PE-HD combines performance and affordability.
Looking for food-safe, UV-resistant, or reinforced PE-HD options? Our team can recommend tailored grades and process settings for your application.