MATERIALS | MEDICAL TUBING


barrier and both tie- or bonding layer, HE said. A traditional approach relies on legacy tubing


products and previous formulations; an optimised approach understands all downstream impacts of material and product characteristics, reviews the complete current portfolio of tubing solutions, works with a tubing supply partner – and ensures all validation and quality considerations are met. He cited an example of an inert tube design for insulin infusion. It required low meta-cresol absorption and adsorption (diffusion through an inert barrier layer), a low extractable product contact layer, an occlusion-free fluid path and no layer-to-layer delamination through tensile shock testing.


Above: Vinyl Healthcare is a new platform for recycling medical PVC


products, it can give consistent flow – due to high resiliency – as well as improved pump service life due to good flex fatigue, biocompatibility and high elasticity.


In an ongoing study, the company has benchmarked its performance in tubing against silicone in peristaltic pumps. Testing is still in progress, but Celanese says it has seen a thousand- fold increase in pump life when using the TPV.


Plasticiser free Aparajita Bhattacharya, senior staff scientist at Kraton, said that TPE can be a viable alternative to PVC in tubing – due to features such as phthalate- and plasticiser-free formulations, good mechanical and optical properties and high flexibility that allows kink resistance. It currently offers a number of blends of Kraton


with PP, but has now developed a styrenic block copolymer (SBC) TPE that can be used on its own in medical tubes. “It can be extruded as a neat polymer without any polyolefin,” she said. The new polymer also showed good solvent bonding properties – with a much higher bond strength than for earlier TPE/PP blends. It also showed comparable bonding to PVC in three solvents (cyclohexanone, THF and MEK). However, PVC tubing has a higher modulus and tensile strength than SBCs. “The inherently higher stiffness and lower


elongation of PVC contributes to its higher solvent bond strength,” said Bhattacharya.


Multilayer benefits Alex Kakad, global product manager at Tekniplex Medical, told delegates that multilayer tubing can help to improve the performance of advanced therapies. Tubes of up to five layers can incorporate gas


20 PIPE & PROFILE EXTRUSION | Summer 2025


In a second, for glucagon delivery, there were additional application requirements: chemical compatibility with DMSO, suspension in 100% DMSO, solvent-bondable to polypropylene luers and fittings, and a complete leak-proof fluid path. “We’ve created a master validation plan to


ensure that validation is performed right the first time,” he said. This usually requires a meeting between the customer’s quality department and the Tekniplex validation team. This ensures that the part is validated to all critical dimensions without adding non-essential elements that can bog down a validation.


Stent delivery Lenny Dao, director of materials science and biocompatibility for acute care therapies at Getinge, explained the challenges in making a PET delivery catheter for an endovascular stent. While the stent itself is made from stainless steel encapsulated in PTFE, the balloon attached to it is made from PET and a thermoplastic elastomer. “Catheter design starts with careful selection of


PET polymer resins,” he said. “A selected PET grade is blended with TPEs to yield the needed properties – including flexibility, tensile strength, burst pressure, compressibility and elasticity.” Resins are processed into subcomponent parts to form the catheter – comprising the PET balloon tube and the extrusion shaft. Extruded tubing is measured using the online and offline equipment to ensure its meets specifications. Optimised PET blends achieve high burst


pressure, enhanced flexibility and kink resistance – with thinner, lower-profile walls,” he said. This makes for improved trackability in complex


anatomies. In addition, antimicrobial reagents and bioactive coatings enhance biocompatibility and reduce thrombogenicity using Immobilize


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