Objective: The goal was to investigate medical grade adhesives that could be good candidates for medical devices expecting exposure to low temperature hydrogen peroxide gas plasma sterilization.
Methods: 36 different adhesives were prepared on various substrates. Adhesives included various epoxies, silicones, cyanoacrylates, and acrylics from 4 different adhesive manufacturers. Samples were prepared such as to challenge the bulk adhesive, not an adhesive joint. The adhesive area measured approximately 1 inch x 0.5 inch by 1 mm thick, open-faced such as to maximize any effects from sterilization exposure. When applicable, samples were cured at the minimum temperature condition recommended by the manufacturer, to represent worst-case curing. Samples were processed in a STERRAD® 100NXTM using the “Standard Cycle” for 100 cycles. Evaluation of the bulk adhesive was by visual observation only.
Results: Of the 36 adhesives, 26 showed no significant material changes after 100 cycles. Of those that did show changes to the bulk adhesive, cracking, foaming, surface blistering, adhesive creep, or hairline fractures were some of the observations. For this list, any color change was not considered a factor of compatibility, since in many applications a color change does not affect the safety or performance of the device.
Table of adhesives with no significant change to the bulk material at 100 cycles:
Loctite M-31 CL
Epoxy Technology 353ND
Master Bond EP30DP MED
Conclusions: This preliminary investigation identified 26 different adhesives that might be good candidates for medical device manufacturers to consider when choosing an adhesive for reprocessable medical devices. Information provided here is for reference only. Testing should be performed by the medical device manufacturer under simulated or actual manufacturing and end-use conditions to ensure acceptable performance for their unique needs.