Skip links

The 5 Most Common Thermoplastics in Injection Molding

Thermoplastic injection molding is the most common way to manufacture parts. Thermoplastics are polymers that can be repeatedly molten or softened and solidified; this is a physical change rather than a chemical change. When beginning the path to a plastic injection-molded part, it is essential to choose the best thermoplastic for your needs.

Here are the six most common thermoplastics used in injection molding.

1. Acrylonitrile Butadiene Styrene

Acrylonitrile Butadiene Styrene (ABS), is an opaque thermoplastic and amorphous polymer. It is a terpolymer containing acrylonitrile, sutadiene, and tyrene. Together, they produce a product that is flexible and versatile enough to use for many everyday products.

You can achieve different outcomes based on the temperature of ABS. Molding at a high temperature improves the gloss and heat resistance while molding at a low temperature is where the highest impact resistance and strength are obtained. The ultimate advantage is that a variety of modifications can be made to improve:

  • Impact resistance
  • Toughness
  • Heat resistance

Additionally, ABS is commonly used in piping systems, plastic clarinets, automotive parts, common household appliances, LEGOs, and more.

2. Polyethylene

Polyethylene – one of the most versatile and popular thermoplastics – is a thermoplastic polymer with a variable crystalline structure and an large range of applications depending on the specific type. The two most common sub-types of this plastic are high-density polyethylene (HDPE) and low-density polyethylene (LDPE). The advantages of polyethylene are :

  • High levels of ductility
  • Tensile strength
  • Impact resistance
  • Resistance to moisture absorption
  • Recyclability

3. Polycarbonate

Polycarbonate (PC) plastics are naturally transparent amorphous thermoplastic. They are used to produce a variety of materials and are particularly useful when impact resistance and transparency are a requirement (ex: bullet-proof glass). PC is unique because it can survive large plastic transformations without cracking or breaks.

PC is commonly used for greenhouses, digital disks like DVDs, eyewear lenses, medical devices, automotive components, and cellular phones.

4. Polyamide – Nylon

Nylon material is used in a large range of different applications because of its electrical properties, toughness, wear resistance and chemical resistance being quite impressive. Nylon has a high level of stability (helps with strength) and is resistant to many external factors like abrasion, impact, and chemicals. This material produces plastic parts used in many industries such as:

  • Medical products
  • Automotive products
  • Sports equipment
  • Apparel and footwear
  • Industrial components

5. Polypropylene

This is a very common plastic that is known for its flexibility. PP (polypropylene) is a very dynamic plastic and has been compounded for a wide range of properties. Some characteristics of this plastic are its high melting point, high resistance to stress and cracking, excellent impact strength, and does not break down easily from reactions with water, acids, and detergents.

PP is safe for use in food containers and other household goods such as utensils, athletic apparel, area rugs, and automotive parts.

Let K&B Help You Choose

Choosing the right material for your application can result in increased performance and reduced cost. The K&B team is proud to provide turnkey plastic injection molding services, from design and development through manufacturing. From material selection to manufacturing methods, we work to ensure that your project is a success. Contact us today for a free custom quote!