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It’s All in The Resin: A Guide to Choosing the Right Material for Plastic Injection Molding

Plastic Injection Molding is rapidly replacing traditional methods of manufacturing as the go-to method of production for B2B and original equipment manufacturers. Here at UPM, we know that choosing the right resin for injection molding is extremely important. That’s why we collaborate closely with each of our customers to ensure that our design and engineering teams understand the unique needs of every client we work with.

Below you’ll find a brief summary of the materials we use in our plastic injection molds. Have questions about a specific polymer? Please don’t hesitate to give us a call at 1-888-893-1587 We’ll be happy to answer any questions you have and discuss the right resin for injection molding your product.

Plastic Injection Molding Resins: Thermoplastic Compounds & Polymers


By far the most common plastic, polyethylene makes up roughly 34% of the total plastics market. Polyethylene comes in many different forms, which makes it extremely useful when it comes to prototyping. Due to its high chemical resistance, it’s also great for use in packaging applications, especially in situations where food is concerned.

Common uses of Polyethylene: Plastic bottles, bags, trays, containers

High-Impact Polystyrene (HIPS)

Sometimes also called “high-impact plastic”, HIPS is also a very widely used polymer that is opaque in nature and is relatively inexpensive. It’s high-impact strength and stiffness are perfect for low strength structural applications that require consistent machinability at an affordable price.

Common uses of HIPS: Home goods, prototype models, indoor signage/displays, automobile components


Similar to polyethylene, polypropylene is a heat-resistant polymer that boasts a high chemical resistance. Polypropylene has the advantage of being tough, but not inflexible, which makes it able to hold up to repeated use. It’s also extremely resistant to absorbing moisture.

Common uses of Polypropylene: Living hinges, piping & fluid applications, food containers, dishes, cups

PVC (Polyvinyl Chloride)

One of the most common types of thermoplastics, PVC is extremely rigid and has similar properties to Acrylonitrile Butadiene Styrene (ABS). PVC has a natural white color and is more dense compared to other plastics. While PVC has a rigid nature, it can be softened and combined with other plasticizers to make it more flexible. PVC is also flame retardant.

Common uses of PVC: Pipes, construction, flooring, electrical cable insulation

Acrylonitrile Butadiene Styrene (ABS)

One of the most common thermoplastic compounds, ABS is known for its impact resistance and toughness. While metal coatings adhere excellently to ABS, it does NOT serve as a good insulator and is prone to melting fairly easily.

Common uses of ABS: Medical devices, interior automobile trim, electronic enclosures, toys (LEGO bricks)


Polycarbonate is mainly used in the manufacturing of electronic and telecommunications equipment due to its superior insulation properties and its ability to be easily molded to tight tolerances.

Common uses of Polycarbonate: Data storage (CDs, DVDs, Blu-Ray Discs), display screens, eyeglasses/sunglasses/eye protection

Nylon (Polyamide)

Nylon is a popular synthetic material that is used in lots of applications that see significant amounts of wear. It can be compounded with numerous additives and fillers to create variants that have different properties and uses. Generally, nylon is relatively long-lasting and elastic, while also being fairly chemical-resistant.

Common uses of Nylon: Clothing, rope/thread, consumer products, packaging film,

Acrylic (PMMA)

Polymethyl methacrylate, more commonly known as acrylic PMMA, is a relatively inexpensive material that is both translucent and rigid. The transparent advantages of acrylic PMMA make it perfect for applications that require high visibility. It is easily molded and can be cut to fit a variety of different forms, all without sacrificing its resistance to UV light and scratching.

Common uses of Acrylic PMMA: As a replacement for glass, light fixtures, safety shields and barriers, LCD screens

Polyetherimide (PEI)

Polyetherimide (PEI) is similar to polycarbonate, but has a higher heat resistance and an impressive impact strength, making it ideal for applications that see continued use at elevated temperatures. Like polycarbonate, PEI is easy to machine and process to exact specifications. PEI is also fairly chemical resistant.

Common uses of PEI: Prototyping & engineering applications, automobile & aircraft products, fiber optics, cookware

Plastic Injection Molding Services from UPM

When it comes to offering design advice, engineering assistance, and help meeting industry regulations, UPM is proud to have a team of experts who will happily guide you through the complete manufacturing process, from the initial consultation to the distribution and shipping of your product.

Interested in talking with someone from our team about which materials would be ideal for your product? Get in touch with us today! A member of our team will get back to you within 24 hours to discuss your project in greater detail.

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