✕
☰

TPU — your flexible friend

by

Fraser Rankin, director of sales and marketing at Permali, discusses TPU and its importance, and growing prevalence, in the medical field. 

Manufacturing products for the medical industry means operating in a highly innovative space, where material, technique and process boundaries are pushed to ensure optimum performance of each individual product and patient care. During the COVID-19 pandemic, the medical sector has increased product development and the turnaround speeds through large-scale production of life-saving products and personal protective equipment (PPE). 

Thermoplastic polyurethane (TPU) has played a large part in this. Its adaptability, range of features and scope of performance means it is perfectly positioned to manufacture within a variety of situations. TPUs can be, depending on the selected grade, biocompatible, sterilised, antibacterial, flexible or rigid, and used for small areas, as well as large-scale applications. 

Understanding TPU

Essentially, TPU is a bridge between rubber and plastic, taking the best properties of both to create a material that can be adapted as required. It can be either polyester- or polyether-based, both of which lend themselves perfectly to different scenarios. These two groups are then further separated into grades to denote property differences, such as hardness, elongation and abrasion loss, all of which vary substantially. 

Tuftane polyester-based TPU grades are known for their abrasion, heat ageing and chemical resistance characteristics. Tuftane polyether-based grades, on the other hand, is used for applications where hydrolysis resistance and microbial performance is key at a variety of temperatures. The Tuftane brand is recognised across many sectors and applications for its tough, highly elastic and flexible film, which can be radiofrequency (RF) welded, ultrasonic welded, heat laminated, adhesive laminated, printed and thermo-formed post-blown film extrusion.1

Polyether is commonly used for medical applications, particularly when comfortable skin contact is preferred, and is formed through a two-part chemical reaction process which can be controlled and adjusted molecularly to change the final TPU grade. Alongside a range of other key properties, changes made to the process can affect specifically the following:

Manufacturing for medical markets

TPU films that will be further manufactured for medical applications, must be created with key chemical properties, and in accordance with strict ISO standards. At a regulatory level, there are broader compliance programs such as the EU’s Directive 93/42/EEC, as well as national regulations.3

To assess the films’ biocompatibility for medical devices, ISO 10993-1:2018, for example, represents safety standards to manage a variety of biological risks.  Tuftane TPU films are regularly assessed to ensure they are compliant for a range of devices and classifications within the medical device sector.

Biocompatibility

Biocompatibility considers whether a material can induce any unwanted response, such as catalysing a reaction or reacting negatively with any other material, skin, human parts or medicines. Medical-grade TPU films are extensively tested to meet standards to guarantee their safety, as the risk here is too high to overlook testing and quality assurance.

As part of the extensive testing of Tuftane TPU films, only certain grades are specified for medical use as per their biocompatibility and suitability. These are typically polyether varieties, although some polyester grades are also included.

TPUs have an inherent resistance to the growth of fungus and microbials. In addition, the material can be sterilised using gamma sterilisation methods to comply with infection control in sensitive medical environments. Silver compounds can be added to TPU formulations to improve a medical device’s resistance to the growth of particularly dangerous microbials, such as methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E-coli).

Medical applications 

Isolation barrier drapes, hoods and robotic sleeves

As TPU can be biocompatible, resistant to bacteria and highly transparent, dependent on grade, it is an increasingly popular material choice in the design of isolation units and robotic arm sleeving. It is also a useful barrier for preventing the spread of infections, protecting expensive equipment and helping to protect staff by creating a bacterial resistant shield, while guaranteeing a level of care and visibility through its transparency qualities. Medical staff can easily monitor the health of the patient, while remaining safe and distant from infection. 

If medical staff do need to get close to a patient, using a TPU-based pressurised hood, fitted with breathing apparatus, will allow them to continue to provide a high level of care, while ensuring their own safety. 

Pressure pads for beds and wheelchairs

Patients confined to wheelchairs or hospital beds can develop pressure sores, which not only add an extra level of discomfort for patients but can also pose a high risk to their health. TPU’s flexibility, resistance to abrasion, durability, as well as its ability to remain sanitary, make it an ideal material for pressure pads, thereby assisting in the longevity and quality of care a patient receives, while maximising their comfort.

Blood plasma bags and similar medical bags

Blood plasma bags must be made from nonpermeable, biocompatible, anti-tear and antibacterial material to ensure their contents are sterile and, therefore, fit for injecting into a patient without any risks. In addition, they must be translucent to help healthcare workers readily identify the bag’s contents. TPU’s translucence, promotes its application for these bags.

TPU, with its weld strength, puncture resistance and medical safety, is also a viable material for colostomy bags, which must be sterile and as discrete as possible.

Protecting healthcare workers during the COVID-19 pandemic

During the pandemic, TPU producers such as Permali were tasked with producing more TPU than ever to assist in the healthcare field. As TPU can be used for a variety of medical applications, including vital PPE, the need for it has never been greater. 

During the crisis, rapid production of PPE and a stable supply chain were key to guaranteeing the safety of front-line workers. TPU producers were instrumental in providing a ready and reliable supply of government-approved TPU, thus supporting PPE and medical safety product manufacturers.

Note: Tuftane is registered trademark of Permali 

Back to topbutton