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February 16, 2011 - Updated
February 14, 2011 - Originally Posted

SMT Adhesive Turning Black

Sometimes our SMT adhesive will turn a black color during storage. We store the adhesive between 5-10 degrees C. What could be the cause of this discoloration, and could it be impacting the adhesive properties?
M. T.
Expert Panel Responses
I need a little more info before I can help. What is the adhesive? Who makes it? I can't answer without knowing a little more. However, the adhesive properties can be evaluated against a control, "known to be good" sample of the adhesive. I suggest using a combination of instruments, such as DSC and TGA, and FTIR to take a look at thermal characteristics of "good" vs "suspect". I can be more specific if I know more about the adhesive itself.

Jim Williams
Jim Williams
Chairman, Polyonics, Inc.
Jim Willimas is a PhD Chemist in Polymers and Materials Science. He specialize in printing, cleaning, inks, and coatings used in electronics manufacturng operations. Williams has more than 30 years experience.
I need a little more info before I can help. What is the adhesive? Who makes it? I can't answer without knowing a little more. However, the adhesive properties can be evaluated against a control, "known to be good" sample of the adhesive. I suggest using a combination of instruments, such as DSC and TGA, and FTIR to take a look at thermal characteristics of "good" vs "suspect". I can be more specific if I know more about the adhesive itself.

Jim Williams
Jim Williams
Chairman, Polyonics, Inc.
Jim Willimas is a PhD Chemist in Polymers and Materials Science. He specialize in printing, cleaning, inks, and coatings used in electronics manufacturng operations. Williams has more than 30 years experience.
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