5 Essential Materials Used in Injection Moulding

Injection Moulding - 2


Injection moulding, a popular manufacturing method, relies heavily on the materials it uses. The material selection can greatly influence the product’s final quality and functionality. Here, we’ll explore some common materials and their unique properties.

Common Thermoplastics

Thermoplastics rank among the most commonly used materials in injection moulding. These plastics can be melted, molded, and then cooled multiple times without significant degradation.

  1. Polyethylene (PE)

    • Polyethylene stands out as the most widely used plastic globally. Due to its versatility, industries choose it for various products. It’s found in everything from plastic bags to toys.
  2. PVC (Polyvinyl Chloride)

    • PVC, known for its rigidity, often gets used in construction. Still, its flexibility can be increased with certain additives. It’s frequently found in pipes, cables, and even clothing.
  3. Polystyrene (PS)

    • Polystyrene, a clear and brittle plastic, often makes its way into packaging materials. It’s the material of choice for products like disposable cutlery and CD cases.

Thermosetting Polymers and Elastomers

Unlike thermoplastics, thermosetting polymers don’t remelt once they’ve been shaped. This feature makes them ideal for high-heat applications.

  1. Epoxy Resins

    • Epoxy resins are strong and resist chemicals. They’re often found in electronics due to their excellent electrical properties.
  2. Melamine Formaldehyde

    • Heat-resistant and stiff, melamine formaldehyde appears in kitchenware like plates and cups. Its ability to retain color and gloss makes it a favorite.
  3. Elastomers

    • Elastomers can stretch significantly without permanent deformation. Items like rubber bands, seals, and gaskets come from this material.

Essential Materials Used in Injection Moulding

Material TypeExamplesPropertiesCommon UsesNoteworthy Statistics
Polyethylene (PE)Versatile, flexible, durablePlastic bags, toys, containersMost widely used plastic globally
PVC (Polyvinyl Chloride)Rigid but can be made flexible with additivesPipes, cables, clothing40 million tons produced annually worldwide
Polystyrene (PS)Clear, brittlePackaging, disposable cutlery, CD cases14.5 million tons produced globally in 2020
Thermosetting Polymers
Epoxy ResinsStrong, chemical-resistant, good electrical propertiesElectronics, industrial toolsMarket valued at $7.77 billion in 2020
Melamine FormaldehydeHeat-resistant, stiff, retains color and glossKitchenware, plates, cupsOver 1.5 million tons consumed annually
General ElastomersHighly stretchable, returns to original shapeRubber bands, seals, gasketsMarket to reach $92.36 billion by 2022

Material Selection Criteria

While the above materials offer varied benefits, their selection often hinges on three main criteria: cost, strength, and flexibility. Industries must weigh these factors against the intended function and lifespan of their products to make informed decisions.

Choosing the right material for a project isn’t random. It revolves around certain criteria that ensure the product’s success.

  1. Cost

    • Affordability often drives decisions. Industries weigh the material cost against the product’s expected lifespan and function.
  2. Strength

    • Some products need to withstand pressure or force. For these, materials with higher tensile strength get the nod.
  3. Flexibility

    • Items that need to bend or flex without breaking require flexible materials. Understanding a material’s elasticity is paramount here.


Materials form the backbone of injection moulding. By understanding their properties and uses, manufacturers can produce high-quality items that meet specific needs. As technology advances, we might see even more materials emerge, expanding the possibilities in this dynamic field.