Steve,
Pictures are worth a thousand words.
I think I am seeing that your white topcoat is separating from the base polyimide label stock. I thought you were saying that you adhesive holding the label onto the surface below was being attacked.
I think this is either sub standard material stock issue or possibly really high spray pressure impingement, and not alcohol degrading the acrylic adhesive below.
Phil
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Monday, June 10, 2013 12:05 PM
To: [log in to unmask]
Subject: Re: [TN] Labels that withstand Wavesolder with alcohol based flux
Hey Richard!
Tried curing them last Friday like you said, but no joy. Still blistering up after wave and/or washing off in our inline DI cleaner.
Here are a couple photos that I didn't post last week:
http://stevezeva.homestead.com/BubblyLabel.jpg
http://stevezeva.homestead.com/BubblyLabelClose.jpg
The labels are polyimide with a white topcoat for thermal transfer printing. They are supposed to be good to 1000 F., but you can see the blistering in the close-up photo. You can also see the adhesive bubbling-up beneath the kapton in the blister at the top of the number 2. When the boards go through the DI wash, the labels either fall off, or are just about to. The adhesive has turned to mush beneath the label.
I still think it's the alcohol attacking the acrylic adhesive. We sent an email to the label manufacturer who said they would forward everything to their process engineering group...still waiting to hear back from them.
Anybody else had this problem?
Steve Gregory
-----Original Message-----
From: Stadem, Richard D. [mailto:[log in to unmask]]
Sent: Thursday, June 6, 2013 2:07 PM
To: TechNet E-Mail Forum; Steve Gregory
Subject: RE: [TN] Labels that withstand Wavesolder with alcohol based flux
Whatever label you use, consider curing them at 90 deg. C for 1 hour.
That helps even common paper labels to be able to withstand wash processes, etc, a little better.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Thursday, June 06, 2013 3:04 PM
To: [log in to unmask]
Subject: [TN] Labels that withstand Wavesolder with alcohol based flux
Hi All,
I know I have had PCB label issues not standing-up to alcohol based flux and wave solder in the past and have found some that worked...but because I'm so absent minded, I forgot which ones they were.
The labels that we are using now are thermal transfer ink printed, they SAY that they can withstand wave soldering processes, but the adhesive is acrylic and the alcohol in the flux attacks the adhesive, and the labels wash off in our DI cleaner.
Anyone got a good recommendation for label stock?
Steve
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