Date:    Tue, 2 Sep 2008 10:43:10 -0500
From:    "Roberts, Jon" <[log in to unmask]>
Subject: ANTISTATIC MATERIAL QUESTION

We have been noticing if bubble wrap is allowed to come in direct
contact with a circuit card assembly (non ESD and ESD) sensitive that
the bubble wrap leaves impression in the AR coating.  Do know if the
resulting impression is related to uncured coating or reaction of the
bubble wrap material?  Thanks for any information, Jon



Jon,

Not to be a stickler on coating questions, but there is no such thing as uncured AR coating. Because the coating is lacquer, it doesn't cure, it only dries. The solvents in which the acrylic resin is dissolved leave the coating and all that is left is the plastic.?That plastic does not cross-link, so it?can be redissolved at will, and that's why AR is the strippable coating that it is.?Insufficient drying?could?contibute to the condition you describe.?In our experience?we believe that plasticizers from the bubble wrap (notoriously oily, nasty stuff, it even seems like the antistatic is worse) are actually redissolving the coating in areas of contact. This would be more noticeable if the coating were not completely dry, since it's already somewhat melted. In any case, our solution is not to let the bubble wrap come into direct contact with any type AR coating.

Mike Moninger
Thermospray Company Inc.

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