Just back from a week off and going through my e-mails and saw this thread.

At one time we had tape dots we used for conformal coat masking.  They became obsolete so we switched to a Shercon product.  I discovered that during the conformal coating process the silicone adhesive in the Shercon product reacted with the acrylic conformal coating Konform AR.  This could be seen after curing, but you could watch the "blooming" if monitored under UV light.

Solution was to find tape dots with acrylic adhesive.  No more bloomimg.

Phil

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge Hernefjord
Sent: Wednesday, August 07, 2013 2:03 AM
To: [log in to unmask]
Subject: Re: [TN] Silicone adhesives on tapes

Hi Richard,

My experience from Shercon is null, little better about PA.

Must be primed with polyurethane/rubber solution + 5% of isocyanate cure.Before this, you should of course do the standard degreasing plus grinding the surface of the PA with grit 600-1200.

PA can also be primed with phenol-resorcinol glue. Same pre-treatment.

It's twenty years since I was involved in the above, many new methods may exist today.

Inge


On 6 August 2013 06:17, Stadem, Richard D. <[log in to unmask]>wrote:

> Do you think the silicone adhesive on Kapton and Shercon tapes can 
> create a manufacturing issue during conformal coating or for sensitive electronics?
> Doug, I would be especially interested in your respected input on this 
> question.
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