New Polyolefins Improve RF Welding Seals

Positive Ramifications for the Medical Industry

Radio Frequency Welding relies on the vibration and orientation of charged molecules within a polymer chain in order to generate heat. As a result, its use is restricted to plastics containing polar molecules. Polyvinyl chloride (PVC) and polyurethanes are the most common thermoplastics to be welded using the RF process. It’s possible to use RF welding on other polymers, such as nylon, polyethylene terephthalate (PET), ethylene-vinyl acetate (EVA) and some acrylonitrile butadiene styrene (ABS) resins, but these require special conditions. Conversely, some polymers, like polytetrafluoroethylene (PTFE), polycarbonate, polystyrene and polypropylene, are not suitable for welding at all.

However, as a result of impending restrictions in the use of PVC, a special grade of polyolefin has been developed which does have the ability to be RF welded. This is good news for the medical industry. Polyolefins are used extensively in the medical industry because they are relatively low cost and have unique performance properties – chemical resistance, inertness and light weight. The two most common polyolefins are polyethylene (PE) and polypropylene (PP), and they are used in applications ranging from syringes to storage bags. But, while their ease of melting is a benefit, bonding polyolefin components can be challenging.  Adhesives and solvents are largely ineffective, and heat bonding can be challenging for the precision welding needed for medical devices.

To combat these welding challenges, the medical industry turned to polyolefin films. Medical bags, protective sleeves, wound care and other applications have used polyolefin films for a number of years. These film-based medical constructions typically use RF welding.  Recently, there has been increased demand for replacing polyvinyl chloride (PVC) films because of concerns about toxicity and plasticizer leaching. The industry has responded by creating multi-layer polyolefins, and new grades of polyolefins specifically designed to improve the precision welding the medical industry is seeking.

The point? Welding for medical care products continues to evolve in an effort to increase the integrity of the seal, and RF welding is at the core of many of those advances. And perhaps the best equipment complement to these new polyolefins are Thermex Thermatron RF Inline Systems. All Thermatron RF equipment is custom-designed to match the needs of our clients. These systems integrate RF technology and efficiency with such options as a heavy-duty unwind stand, an automatic indexer and multiple RF welder stations – each with its own PLC with PC interface controls. This makes them perfect for welding from rolled material for products like blood or IV cuffs, colostomy or enema bags, and other medical products and devices.

To learn more about Thermex Thermatron’s RF Inline Systems and experience in medical manufacturing, contact Mark Isgrigg at 502.493.1299 x202 or mark@thermex-thermatron.com.z