Question: Can medical silicone be bonded to thermal plastic parts?
Answer: Medical silicone can be bonded to some thermal plastics such as polycarbonate, nylon, polybutylene terephthalate (PBT), and others. Bonding medical silicone can be improved with material selection, surface treatments, adhesives, and primers but many of these fail biocompatibility limiting their medical applications. Many thermal plastics don’t have enough thermal resistance to withstand over-molding temperatures while others bond poorly with liquid silicone such as polyethylene and polypropylene. Surface treatments like heating or flame, scratching, corona, plasma, and others can assist bonding. Adhesives and primers can be effective but they can add significant cost and cause problems with biocompatibility. There are some vendors that make implantable self adhesive silicones, adhesives, and primers but there aren’t a lot of options. One additional consideration is that materials (medical silicone, plastics, etc) from different vendors have different formulations and may result in significant differences in bond strength of the liquid silicone.