Foster Corporation now offers thermoplastic urethanes (TPU) with PureEase technology for improved extrusion processing control. This proprietary additive system was developed to help maintain consistent processing parameters of validated TPU based polymers and compounds. Consistent processing parameters can mean tighter ID/OD tubing tolerances especially in small tubes.
PureEase technology is available in custom TPU based compound formulations used in radiopaque filled tubing applications commonly used in central venous catheter (CVC) tubing. It can also be beneficial in unfilled TPU polymers as well, in applications where tight tolerances are necessary such as wound care films.
TPU’s are inherently tacky and this tackiness can present challenges for processors. A common problem during the production of medical tubing and film is adherence to the die as the hot melt exits the extruder. This phenomenon can distort the final tube shape which can result in components that are outside required dimensional specifications. The PureEase technology can help with this problem.
Foster compared extrusions of single lumen tubing with nominal outside diameters of 0.11 in. (2.8 mm) using 55 Shore D hardness TPU with PureEase technology against the same TPU without the additive. Using the same processing conditions, the extrusions with PureEase technology had a diametrical standard deviation of 0.0012 in. (0.03 mm) compared to 0.0025 in. (0.06 mm) for the unmodified sample, representing 50% less dimensional variation. Similar extrusions performed with barium sulfate-filled 55 Shore D TPU resulted in 53% less variation of diametrical dimensions for the sample with PureEase technology compared to a similar compound without the additive.