HDPE.
High-density PE.
Chemical-resistant.
HDPE (High-Density Polyethylene) — tough, chemical-resistant, low-cost commodity plastic. Ideal for chemical containers, piping, cutting boards, food contact applications.
Key principles.
Semi-crystalline
Density 0.94-0.97 g/cm³. Higher density than LDPE means higher stiffness, strength, chemical resistance.
UTS 25-32 MPa
Lower strength than engineering plastics. Excellent toughness, low friction.
Excellent
Resists acids, bases, alcohols, most solvents. Limited only by aromatic solvents at temperature.
Food contact
FDA-listed for direct food contact (21 CFR 177.1520).
Cheapest plastic
~$1.50-2/kg. Among cheapest engineering plastics.
Low temperature only
Service temp -50°C to +80°C. Above 80°C, deforms.
FAQ
HDPE vs LDPE?
HDPE: stiffer, stronger, chemical-resistant. LDPE: more flexible, transparent. Both polyethylene, different density.
Welding HDPE?
Hot air welding or extrusion welding. Common for chemical tanks, water treatment.
Machining HDPE?
Soft, flexible, gummy. Sharp tools, slow speeds. Stress-relieve before machining for stable dimensions.
UV stability?
Carbon-black UV-stabilized grades 20+ year outdoor. Standard HDPE 1-3 years before degradation.
Recycling?
Recyclable (#2 in resin code). Major commodity recycling stream.
Best applications?
Chemical containers, water pipes, milk jugs, cutting boards, marine fenders.