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January 2009

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Subject:
From:
Brian Ellis <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Brian Ellis <[log in to unmask]>
Date:
Wed, 7 Jan 2009 08:25:33 +0200
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Many, many years ago, I did a study on this subject and found that pink 
a-s plastic came with a variety of hygroscopic chemicals, many of which 
had sufficient vapour pressure and recondensed on the assemblies, even 
without physical contact. Plasticisers, albeit less hygroscopic, as a 
rule, did the same. One of the popular materials used as an additive was 
PEG with MWs in the order of 1000s. I don't know whether it is still 
used. The glycol ends of the chain were sufficiently hygroscopic. The 
material under question was plasticised PE and anyone who thinks PE 
affords any protection, except against dust, need his head examining. It 
is like a sieve!

Brian

Joe Macko wrote:
> Hi All.
> 
>  
> 
> My question is related to a comment one of our CMs recently made about
> not allowing populated/soldered boards to come in direct contact with
> pink colored antistatic foam for extended periods of time. This CM was
> notified by another customer that they observed discoloration of solder
> joints, solderability issues and /or conformal coat adhesion problems
> after ~ 90 days due probably to either out gassing and/or a chemical
> reaction with the ant-stat chemicals used in the foam. At one time I did
> hear about N'octonic acid (not sure of spelling) in pink poly static
> bags causing problems but have not heard anything recently.
> 
>  
> 
> Has anyone heard of or experienced such issues with the use of such
> material as pink colored antistatic foam?  Is there a safe anti-stat
> foam that does not have these issues/concerns?  Is there a mil spec or
> some other industry type spec that regulates the type of anti-stat
> material used with electronics?  thanks
> 
>  
> 
> Best Regards,
> 
> -Joe
> 
>  
> 
> 
> "This e-mail and any attachments are solely for the use of the addressee and may contain L-3 proprietary information that may also be defined as U.S. Government export controlled technical data. If you are an unintended recipient of this e-mail, use, disclosure or distribution of its content is prohibited. Please notify the sender by return e-mail and immediately delete this message."
>  
> 
> 
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