HDPE Injection Moulding Material

What is High-Density Polyethylene (HDPE)?

High-density polyethylene (HDPE) is often regarded as a “cheap and cheerful” thermoplastic polymer for plastic injection moulding. It is a resin found typically in pellet form and designed to provide excellent processability for moulders. It can withstand high impact, possess high-stress crack resistance, and have extreme durability.

Injection moulded HDPE material properties

Advantages of HDPE Injection Moulding

• Affordable — HDPE can’t compete with engineering plastics in terms of performance, but it’s an attractive, low-cost option for many applications.
• Excellent Impact Resistance — Injection moulded HDPE has exceptional toughness and impact resistances flowing it to withstand heavy loads and impacts without deformation or breakage.
• Chemical and Moisture Resistance — HDPE is highly resistant to a wide range of chemicals (such as acids, bases, and solvents) and does not swell or degrade in wet environments. This makes it highly suitable for applications in the agricultural and industrial sectors.
• Good UV Resistance — HDPE can withstand prolonged exposure to sunlight without significant degradation, making it ideal for outdoor applications.

Disadvantages of HDPE Injection Moulding

• Lower Strength and Stiffness — HDPE has lower strength and stiffness compared to engineering plastics like ABS or nylon (PA).
• Limited Temperature Resistance — HDPE has lower heat resistance. It softens around 120°C and when exposed to temperatures exceeding 340°C, it will begin to burn. This limits its suitability for high-temperature applications, although flame-retardant HDPE grades are available.
• Poor Bonding Qualities — HDPE is a low surface energy (LSE) material, making it difficult to bond with adhesives, paints, and overmoulding materials—just like polypropylene (PP). This poor adhesion is why HDPE is generally not suitable for overmoulding.
• Limited Design Flexibility — HDPE’s flow characteristics and shrinkage behaviour can make it challenging to achieve intricate details or thin walls without encountering moulding defects like sink marks or warpage.

What Is HDPE material Used For?

HDPE is a versatile material with a wide range of applications across the automotive, electronics and many other industries. Some common applications include:

• Agricultural pipes
• Plumbing components
• Food and beverage containers
• Medical tubes
• Recycling bins
• Cleaning product bottles

Alternatives to HDPE

Polypropylene (PP)

If your application will be exposed to moderately higher temperatures or requires a more flexible material, PP is a good alternative to HDPE. PP is a commodity thermoplastic with good fatigue strength, a low coefficient of friction, and excellent moisture resistance. It is typically as affordable, or sometimes even cheaper than HDPE, making it an equally viable and cost-effective alternative in many applications.

Nylon

When your part requires more mechanical strength, abrasion resistance, or heat resistance, Nylon is a good alternative to HDPE. Nylon is highly durable, with exceptional strength and resistance to wear and tear, and it can be filled with glass fibers for enhanced properties. It’s worth noting that nylon is hydrophilic, so it’s not ideal for injection molded products where there’s continuous contact with water.

Get Custom Injection Mould Parts in HDPE material

At HLH Rapid, we offer an extensive selection of resins to meet your custom injection molding needs, including High-Density Polyethylene (HDPE). To begin your next project, simply upload your CAD drawings using our contact form and provide the project details, such as quantity, material choice, and any surface finish requirements. Our dedicated team will respond with a quote within 48 hours or less.