10 Most Commonly Used Plastic Injection Molding Materials

As it directly affects the molding operation and the part performance, choosing the right material is one of the most important things of any product development project. Being one of the most widely used plastic formation techniques with countless industrial applications, plastic injection molding material selection is no exception. And with over 85 thousand types of materials to pick from, you can picture how overwhelming it can get for entrepreneurs, product designers, and engineers to pick the right material to manufacture their product. 

     Photo from Pinterest

Speaking of injection molding makers, one of the most important tasks they have is to find and use lasting and corrosion-and-temperature resistant materials for the products they are going to produce. Finding the right material means they will be able to produce components with greater longevity as well. In recent years, the use of eco-conscious biodegradable materials started to gain traction in various industries since they have lower impact on the environment. So, how do you make sure you pick the right material for the injection process? 

When picking the plastic material you’ll use, first and foremost, you have to consider the part’s function and its environment. In other words, you need to find an answer to what material would be best suited for the specific part’s application. It’s much easier to come up with this answer when you look into the overall material composition that plastics used for injection molding fall into. After that, durability, flexibility, material strength, color, and cost come into play. To help you better understand the numerous materials available on the market, we’ve compiled a list of the top 10 most commonly used plastic molding materials and their applications. 

Nylon (Polyamide) 

Nylon or Polyamide is commonly used to produce strong mechanical parts. Gears, bushings, and bearings are just a couple of automotive parts produced using this material. Nylon is tough, melts at a high temperature, and it comes with great chemical resistance. This material finds great use in the manufacturing of quick-release buckles, as the grand majority of buckles you’ve ever seen in your life were made using this material. This plastic material is also known by its chemical designation PA. 

Photo from Pinterest

Polycarbonate

Polycarbonate comes with fantastic optical properties and is extremely durable. While molding with this thermoplastic material, accurate dimensional control can be preserved as it has very predictable and uniform mold shrinkage. Makers use polycarbonate when they need something substantially stronger than acrylic. However, polycarbonate is not suitable for food storage as it contains Bisphenol-A. This material is widely used in the making of compact discs. 

Photo by 500photos from Pexels 

Acrylic

Acrylic is massively used in the production of transparent parts like windows, transparent walls, and different lighting equipment. Makers use it as an alternative to glass due to its high tensile strength and weather and scratch-resistant nature. Acrylic also comes with many unique qualities besides optical and transparent properties. Unlike Polycarbonate, this material is commonly used for the storage of food, as it’s odorless, tasteless, and doesn’t contain the harmful organic synthetic compound Bisphenol-A.

Polyoxymethylene (POM) 

POM is a kind of acetal resin used for producing automotive and mechanical parts that would usually be made with metal. As a widely used thermoplastic material, POM is very strong, tough, and rigid. Even though POM has high resistance towards solvents, it really should not be exposed to hydrochloric acid and nitric acid. This engineering material is often used to produce gears, fasteners, knife handles, and ball bearings. 

Acrylonitrile Butadiene Styrene (ABS) 

ABS is an opaque thermoplastic polymer and an engineering grade plastic. This material is pretty durable, comes with great dimensional stability, high impact resistance, resistance to scratching, breaking, or tearing. ABS is relatively inexpensive and has a low melting temperature. It’s widely used for the production of electronic parts such as keyboard keys, phone adaptors, and wall socket plastic guards. 

Photo by Sathesh D from Pexels

Polystyrene (PS)

Speaking of the plastic injection molding process, there are two types of polystyrene that are frequently used: High Impact Polystyrene (HIPS) and General Purpose Polystyrene (GPPS). GPPS is transparent and HIPS is more opaque. HIPS is used for the production of hard cases for toolboxes, and bodies of power tools. While Poystyrenes come at a very affordable price, they are certainly not one of the most eco-friendly plastic materials.  

Polyethylene (PE) 

This plastic is a lightweight thermoplastic material with high chemical resistance, electrical insulating properties, and a great level of elasticity. It’s definitely not the strongest and hardest material out there, but it’s still frequently used in producing everyday products like milk bottles, medicine bottles, plastic bags, and trash cans. Polyethylene is the most used injection molding plastic-type in the production of kids’ toys. 

Polypropylene (PP) 

Polypropylene is broadly used in the food storage and packaging industry because it doesn’t let chemicals mix with food products. PP has high chemical and moisture resistance, and it can be washed in hot water without degrading at all. 

Thermoplastic Polyurethane (TPU)

This plastic is very soft and comes with a great level of elasticity. It’s often used to produce parts that demand rubber-like elasticity. Thermoplastic Polyurethane performs really well at high temperatures and is commonly used in the production of power tools, cable insulations, and phone cases. 

Photo by Burst from Pexels 

Thermoplastic Rubber (TPR) 

As TPR is most often a mix of plastic and rubber, it exhibits properties of both materials. It comes with outstanding chemical and weather resistance and high impact strength. This highly recyclable material is extensively used in the production of medical catheters, suspension bushings, and headphone cables. TPR is also known as Thermoplastic Elastomer (TPE).