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Engineering Resins & PEEK Tubing
PEEK, polyetherimide, polysulfone, polycarbonate and PBT tubing for medical devices that need strength, stiffness and heat resistance.
What are engineering resins?
Engineering resins are a group of plastic materials that combine great strength with light weight over a wide range of conditions. They are usually chosen for one or more enhanced physical properties. Polycarbonate (PC) is known for its impact resistance, for example, and polybutylene terephthalate (PBT) for its dimensional stability. Other characteristics of some engineering resins are high heat resistance, rigidity and chemical stability.
Most engineering resins perform better at temperatures above 275°F (135°C) than commodity plastics do. That makes them a good fit for medical tubing that must survive repeated sterilization, carry load, or stay straight and stiff where a softer material would bend.
Crystalline and amorphous resins
The term “engineering resin” usually refers to thermoplastic materials. Thermoplastics are elastic and flexible above each resin’s specific glass transition temperature. Depending on the temperature, most thermoplastics have a crystalline region, which gives them strength and rigidity, and an amorphous region, which gives them elasticity.
Resins that do not crystallize are called amorphous. Polycarbonate, polyetherimide and polysulfone are amorphous, so they soften over a range instead of melting at a sharp point, and they are most often chosen where clarity matters. PEEK and PBT are semi-crystalline, with a true melting point and strong resistance to heat and chemicals.
Choosing a resin for your tube
| Resin | Structure | Known for |
|---|---|---|
| PEEK | Semi-crystalline | Exceptional strength and toughness across temperature extremes, moisture and chemical attack |
| Polyetherimide (PEI) | Amorphous | Heat and hydrolysis resistance, withstands multiple autoclave cycles |
| Polysulfone (PSU) | Amorphous | Highest service temperature of the melt-processable thermoplastics, strength and transparency |
| Polycarbonate (PC) | Amorphous | Toughness, transparency and higher impact resistance than nylon 6 and 6,6 |
| PBT | Semi-crystalline | Dimensional stability, stiffness and strength for complex thin walls |
Engineering resins are rigid, ranging from somewhat rigid to very rigid, with tensile strength from about 10,000 to 16,000 psi. They are generally not suitable for remaining in the body for 30 days, so they are best suited to devices and components with short contact times or no patient contact.
PEEK tubing
PEEK tubing is the most requested engineering resin tube we make. PEEK holds its strength and toughness through temperature extremes, moisture and chemical attack, and it tolerates steam autoclaving and vaporized hydrogen peroxide. That makes PEEK tubing a strong choice for reusable instruments, stiff support tubes, and liners or jackets that must stay dimensionally stable. We also extrude thin wall PEEK, with walls held as thin as 12.5 microns. See the PEEK datasheet for full property values.
Sterilization
Depending on the resin, engineering resin tubing can be sterilized by ethylene oxide, gamma and E-beam radiation, steam autoclaving and vaporized hydrogen peroxide. PEI handles repeated autoclaving especially well, and PEEK holds its properties through steam and hydrogen peroxide cycles. Check each datasheet for the methods that apply.
On this page
Quick facts
| Hardness | Somewhat to very rigid |
| Tensile strength | 10,000 to 16,000 psi |
| Vicat softening | 286 to 426°F |
| Biocompatibility | Not for 30-day implant use |
| Quality system | ISO 13485:2016 |
High-heat tubing?
Tell us the temperatures and sterilization cycles your part will see. We will help you pick the resin.
Performance
Why engineers reach for these resins.
Heat resistance
Better performance above 275°F than most plastics.
Strength
Tensile strength from 10,000 to 16,000 psi.
Dimensional stability
Holds tight dimensions, even in thin walls.
Chemical stability
PEEK and PBT resist chemical attack.
Clarity
Amorphous grades like PC and PSU can be transparent.
Repeat sterilization
Autoclave, EtO, radiation and VHP, by resin.
Resins we extrude
Engineering resin datasheets.
Full property values for each resin we run.
Semi-crystalline
PEEK
Exceptionally high strength and toughness, holding its properties through temperature extremes, moisture and chemical attack.
| Melting point | 644 to 649°F |
| Tensile | 16,000 psi |
Amorphous
Polyetherimide (PEI)
Heat and hydrolysis resistant and able to withstand multiple autoclaving cycles. Similar to PEEK with lower temperature resistance.
| Glass transition | 410 to 421°F |
| Shore D | 109 to 112 |
Amorphous
Polysulfone (PSU)
Holds its properties over a wide temperature range, with excellent strength and transparency. It can be colored.
| Glass transition | 370°F |
| Water absorption | 0.22% to 0.3% |
Amorphous
Polycarbonate (PC)
Excellent toughness, strength, transparency and color stability. Lower resistance to chemicals and organic solvents.
| Glass transition | 302°F |
| Tensile | 10,000 psi |
Semi-crystalline
Polybutylene Terephthalate (PBT)
High heat resistance, stiffness and hardness, with high dimensional stability for complex thin walls.
| Melting point | 437°F |
| Shore D | 78 |
Working with a resin that is not listed? Send us the details.
Keep exploring
Related materials and extrusions.
Nylon tubing
Pushable, lubricious and pressure resistant.
Fluoropolymer tubing
FEP, PFA and EFEP for low friction and chemical resistance.
Profile extrusions
Rigid non-round shapes where stiffness matters.
Questions
Engineering resin tubing, answered.
Have a question about high-performance tubing? Ask us.
What is PEEK tubing used for in medical devices?
PEEK is chosen when a tube needs very high strength and toughness that hold up through temperature extremes, moisture, chemicals and physical stress. It also tolerates steam autoclaving and vaporized hydrogen peroxide, which suits reusable and heavily sterilized components.
What is the difference between PEEK and PEI?
Both are high-performance polymers with similar characteristics. PEI is amorphous, heat and hydrolysis resistant and handles multiple autoclave cycles, but it has lower temperature resistance and lower impact strength than semi-crystalline PEEK.
Can engineering resin tubing be autoclaved?
Most of the resins we extrude can be steam autoclaved, polycarbonate only to a limited degree. PEI is known for withstanding multiple autoclaving cycles. Each datasheet lists the sterilization methods for that resin.
Are engineering resins biocompatible for implants?
Our material data lists engineering resins as not suitable for remaining in the body as long as 30 days. Confirm biocompatibility for your specific device and grade with the resin supplier.
Why choose an amorphous resin?
Amorphous resins such as polycarbonate and polysulfone do not crystallize, so they are often chosen where clarity is important. They soften over a range around their glass transition temperature instead of melting sharply.
Need tubing that takes the heat?
Send us your specs, drawing or just describe the problem. A member of our team will follow up personally to walk through tolerances, materials and schedule.
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Have full drawings and tolerances? Use our detailed request form.