 Nadine Blaesing Dymax Corp. Market Segment Manager Visit Website |
Nadine Blaesing is the market segment manager, Europe, for Dymax. She has more than 12 years of experience selling adhesives and providing technical assistance to the medical device market. Although she began her career as an applications engineer in Europe, and later in the United States, Blaesing eventually transitioned into marketing while keeping her focus on the medical device industry. Dymax specializes in the manufacture of light-curable adhesives, cyanoacrylates, epoxies, light-emitting curing equipment, and dispensing systems.
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Adhesives and Epoxies Q&A
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We have an application in which a ½ × ½ x 1-in. bar is inserted to a depth of ½ in. in a ½ × ½-in. hole machined on a flat bar. Both parts are made of anodized 7075 T6 aluminum alloy. The inserted bar receives intermittent torque around the long axis. We are using common two-component epoxy adhesive manufactured by DuPont. After assembling, the parts are heated to 260°F for sterilization purposes. The results are rather poor: After being in use for a short period of time, the parts become loose and separate. Is there a product that we can use as a substitute?Answered August 25th, 2010 by Expert:There are a couple of choices that come to mind based on your application. Several epoxy options can survive these temperatures and exhibit good adhesion. Dymax ER1196/CT1196 has shown good adhesion up to 285°F. Epotek 353ND is very popular for these types of medical applications. And Epotek 375, which is classified as a high-temperature epoxy, can also be used. Basically, any epoxy that is designed for rugged or ruggedizing applications will be more flexible (i.e., less brittle) so that it can absorb the torsional strain.
Another option is high-temperature epoxies that move the glass transition temperature (Tg) above the sterilization temperature. A typical epoxy can have Tg values in the 80° to 120°C range. When it undergoes sterilization at 260°F/126°C, it crosses this glass transition temperature. An epoxy with a process temperature higher than the Tg value will exhibit more rubberlike behavior, while an epoxy with a process temperature below the Tg value will exhibit more glasslike behavior. Moving the part through this transition (change in temperature) causes stress in the bond line. A high-temperature epoxy should have a Tg above the sterilization temperature so that the bonded part does not have to experience this transition.