General Purpose Tubing
For many single-use medical tubing applications, such as intravenous (IV) lines, transparent polymers are required for clinicians to assess fluid or gas flow through the tube. These tubes require polymers that are resistant to a wide range of cleaning agents and sterilization methods, and must be readily bondable to injection molded fitting and connectors. Common applications for such tubing include:
- Intravenous (IV) tubing
- Umbilical artery catheters
- Infusion tubing
- Nasogastric tubes
- Peritoneal dialysis tubing
- Hemodialysis tubing
The two most commonly used catheters in the medical device market are the urinary catheter and the vascular catheter.
Urinary catheters are used to collect and drain urine from the bladder, diagnose disorders in the lower urinary tract, monitor urine output, and introduce medication. For maximum flexibility, low durometer polymers, such as soft TPU and Pebax resins, including Isothane 5075A, Pebax® 2533 SA 01 MED and Pebax® 3533 SA 01 MED are considered. TPU resins are often selected for their inherent ability to soften in the body, while Pebax polymers provide a unique combination of strength and elasticity.
Vascular catheters are used to gain access to the blood vessels of the human circulatory system in order to perform a variety of diagnostic and therapeutic procedures depending on the type of device.
- Central Venous Catheters are used when patients need IV medicines and fluids. The catheter is usually placed into a vein on the inside of the arm and can remain for several weeks. One or more small tubes with caps provide regular access for clinicians. For improved patient comfort, low durometer polymers, such as Isothane 5075A, Pebax® 2533 SA 01 MED and Pebax® 3533 SA 01 MED, are considered for these in-dwelling catheter applications.
- Diagnostic Catheters are used to diagnose blockage of the artery, often deep within the vascular pathways. For optimal rigidity to push the catheter to the designated site while still maintaining flexibility to navigate vascular pathways, Pebax® 7033 SA 01 MED and 7233 SA 01 MED are often considered. For improved rigidity and pushability Rilsan® BMNO and Rilsamid® AMNO are considered.
- Guiding Catheters are used to navigate to a designated site and then allow the physician to pass a variety of instruments through the catheter for treatment, including a balloon dilation catheter, stent delivery catheter, and ablation catheter. Guide catheters are often complex constructions with braid reinforcements, lubricious liners and varying materials along that length. Lubricous lines may use low friction fluoropolymers, such as Kynar Rx® 752. Outer layers of these catheters may use Pebax® 7233 SA 01 MED at the proximal end for pushability and Pebax® 3533 SA 01 MED at the distal end for flexibility.
- Angioplasty Catheters, also known as PTCA catheters (percutaneous transluminal coronary angioplasty), include balloon dilation catheters and stent delivery catheters. Balloon dilation catheters are used to compress the blockage or stenosis against the artery wall. Stent delivery catheters are used to install a stent inside the artery to support arteries that are weakened by the stenosis. Pebax® 7033 SA 01 MED and Pebax® 7233 SA 01 MED provide flexibility to navigate the vascular pathways to the blocked region and the necessary mechanical strength for transmission of insertion forces and resistance to internal pressure to inflate balloons.
Tie LayersCatheter constructions are often comprised on multi-layer extrusions to enable complex devices with a unique hybrid of material properties. However, often times materials used within these multi-layer constructions (such as Pebax®, TPU and HDPE), are not compatible. Tie-layers are therefore designed to bond materials that typically will not adhere to each other during processing. These layers are often comprised of copolymer blends containing EVA.
Extrusion Cores & MandrelsPrecision medical device components, such as catheters, often require mandrels to support thin wall sections and retain tolerances during manufacturing. These mandrels are commonly made for polymers that must resist heat and chemicals during manufacturing and have exceptional release properties, as measured by surface tension, so that the finished part can be easily removed. TPX™ polymethylpentene (PMP) olefin copolymer has a melting point range of 220°C-240°C (428°F-464°F) and a surface tension 38% lower than high density polyethylene (HDPE), a common mandrel material used for catheter manufacturing. TPX™ olefin copolymer has a specific gravity of 0.83, which is 13% lower than HDPE and represents the lowest density of any commercially available thermoplastic.