Machine Design

Medical product companies turn to specialized RF welding to replace PVC

ecoGenesis can be used to plastics weld a variety of medical devices, supplies and equipment, such as this inflatable bladder used under hospital mattresses to prevent bed sores.

The usual way to connect two TPEs is to heat them up and melt them together. But Radio Frequency (RF) welding can be a better method when the plastics are made of polar resins with high dielectric loss factors. RF welding works quickly and the welded material can be handled coming off the machine.

The problem with the RF welding process is that non-polar plastics are “invisible” to RF energy unless modified with significant amounts of polar additives such as EVA (ethylene vinyl acetate).

Genesis Plastics Welding in Fortville, Ind. has a proprietary technology which was developed in the 1980s called ecoGenesis Plastics Welding.  This technology can seal polar and non-polar plastics such as polyethylene and polypropylene. It may be particularly useful for medical device makers that want to replace PVC with environmentally friendly TPEs for use in disposable, single-use medical products.

The difference between common RF welding and ecoGenesis lies in a proprietary bolt-on technology.  Common RF welding requires a buffer underneath the plastics being welded to prevent holes and over-stimulation of the polar molecules.  Instead of a buffer, ecoGenesis incorporates a durable mechanical catalyst that makes RF energy visible to non-polar materials and weldable in a number of substrates including film, foam, wovens and non-wovens.

Because there’s no need for additives to boost polarity, the material and overall process costs are less.  With ecoGenesis, more types of plastics such as TPE can be welded.

Utilizing turn tables, in-line indexing and single and double shuttle trays, the company can weld film up to 82x42-in. and 0.00025-in. thick. Most film, co-extrusions, multi-laminates, wovens, non-wovens, foam and fabrics can be welded with this licensable technology. Types of plastic include: polyethylene, polypropylene, polyester, nylon and bioplastics.

More information:  Genesis Plastics Welding

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