Preliminary Investigation of Adhesive Compatibility after Sterilization by Low Temperature Hydrogen Peroxide Gas Plasma

Background: We tested various medical grade adhesives that are used in the manufacture of reprocessable medical devices.

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^® 100NX^TM 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 Loctite M-21 HP Loctite 3942 Loctite 3981 Loctite 3381 Loctite 3933 Loctite 3922 Loctite 3972 Loctite 3556

Epoxy Technology 353ND Epoxy Technology 354T Epoxy Technology 302-3M Epoxy Technology OE184 Epoxy Technology 375 Epoxy Technology 354 Epoxy Technology 377 Epoxy Technology 310M-1 Epoxy Technology OG214 Epoxy Technology OG603

Master Bond EP30DP MED Master Bond EP62-1MED Master Bond EP45HT MED NuSil MED2-4013 NuSil MED-1011 NuSil MED-1000 NuSil MED-1137

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.