Medical products cover a large range of categories, including medical devices, imaging equipment, surgical instruments, monitoring devices, assistive devices, in vitro diagnostics, medical/surgical supplies, and PPE. Because of this diversity, a thermoplastic that works well for one, e.g., radiation glasses, may not work as well for another, e.g., a sterilization tray. How the product is used and the environmental and mechanical conditions it is exposed to will play a significant factor in which thermoplastic is best suited to meet its needs.
Characteristics of Plastics Used in the Medical Market
Since medical products encompass a wide range of applications, the primary characteristics of the thermoplastics will vary depending on the specific product. However, there are some preferred characteristics. Often, plastics with these characteristics – biocompatibility, sterilizability, chemical resistance, physical and mechanical properties – are referred to as medical grade.
Technically, the Food and Drug Administration (FDA), which is responsible for approving medical devices, does not have a definition for medical-grade plastic. However, they do regulate the materials used in medical devices through various guidelines and requirements. The FDA regulates medical devices based on their risk category (Class I, II, or III). The higher the risk a device poses, the more stringent the material requirements become. Products regulated by the FDA can be found in its product classification database, which provides recognized consensus standards that may include materials and other specifications. Medical products that are not medical devices, while not addressed in the database, may have regulatory or industry requirements.
Some common characteristics include:
- Biocompatibility—The material should not cause adverse reactions when in contact with the body. This includes resistance to tissue rejection and inflammation.
- Sterilizability— The material should be able to withstand repeated sterilization processes like autoclaving or gamma irradiation without degradation.
- Strength and Durability—Depending on the product’s function, it might need to withstand impact, stress, and repeated use.
- Radiolucency (for imaging devices)—The material should permit X-rays to pass through it partially to allow for visibility.
- Chemical Resistance —The material needs to be compatible with the drugs it carries or contacts and not leach any harmful chemicals
Specific Thermoplastics Often Used for Medical Products
There are hundreds of thermoplastic materials, but some are better suited for medical products than others. While covering every thermoplastic that could be used is impossible, below are some commonly used thermoplastics.
PEEK (Polyetheretherketone) is a versatile material valued for its high strength, stiffness, and biocompatibility. It offers excellent chemical resistance and can withstand high temperatures without deformation. Due to its impressive properties, Peek finds itself in various injection-molded medical applications, including catheter components, specific implant parts, and surgical tools.
Acetal (Polyoxymethylene), also referred to as POM, is a strong and stiff plastic with low friction and good dimensional stability. It offers excellent wear resistance and machinability, making it suitable for various medical device housings. Copolymer Acetal (POM-C) can withstand sterilization methods, such as ethylene oxide and steam autoclaving.
PEI (Polyetherimide) is a high-performance plastic known for its outstanding heat resistance, strength, and flame retardancy. It also offers good chemical resistance and dimensional stability. Due to its heat resistance and mechanical properties, PEI is used in device housings that require high-temperature tolerance, surgical instruments, sterilization trays, and dental devices.
PSU (Polysulfone) offers high strength and stiffness as well as heat and chemical resistance. It is commonly used for analytical instrumentation, medical devices, and surgical instruments.
PET (Thermoplastic Polyester) is a non-hygroscopic plastic valued for its clarity and strength. It has excellent chemical resistance, making it suitable for pharmaceutical containers. It is also used for disposable medical devices, diagnostic equipment, and surgical instruments.
PPSU (Polyphenylsulfone) is a high-performance plastic known for its exceptional heat and chemical resistance and good biocompatibility. It offers excellent dimensional stability and can be sterilized repeatedly with various methods, making it ideal for products where steam autoclaves are used, such as sterilization trays and dental and surgical instrument handles.
Trust Ensinger For Your Thermoplastic Medical Products
Developing medical products requires unparalleled precision, control, and quality. At Ensinger Precision Components, we provide crucial solutions for your critical medical projects. We offer a wide range of high-performance medical-grade materials that are biocompatible, sterilization resistant, and low-density, making them ideal for compliant medical products.
As a leader in plastic manufacturing, our capabilities include injection molding, CNC machining, and advanced manufacturing services such as heat staking, ultrasonic welding, packaging, and more. As part of the global Ensinger organization, we can access resources from other divisions, enabling us to expand our capabilities and services to support your needs.
Ready to address your medical product challenges? Contact Ensinger today to discuss how our expertise can help you deliver products that will make a difference in the lives of patients and medical professionals.