Many thanks to all,
Tom, David and Richard...

I went through  IPC-1601 A, IPC-4553 and also 4552 (2017/8).
Now it is clear.

Best Regards
Gabriele

-----Messaggio originale-----
Da: TechNet [mailto:[log in to unmask]] Per conto di Stadem, Richard D
Inviato: mercoledì 24 gennaio 2018 14:56
A: [log in to unmask]
Oggetto: Re: [TN] Sulfur Free Paper and Acid Free Papaer ?

Silver Saver paper is also fully discussed in IPC-4553 section 3.8, where it is described as both sulfur-free AND pH-neutral (non-acidic). There is also good information on the proper positioning of the desiccant inside the bundle, where it cannot make direct contact. What is little-known is that the desiccant must also be sulfur-free. It is a hard requirement for the desiccant, tapes, labels, markers, rubber bands, if used. The standard says to exclude these materials from the drypack, but if used they must be sulfur-free.
The debbil is in the details!

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
Sent: Wednesday, January 24, 2018 7:21 AM
To: [log in to unmask]
Subject: Re: [TN] Sulfur Free Paper and Acid Free Papaer ?

Hi Gabriele - in addition to the info that Tom provided, the IPC-1601A specification has some information on "Silver Saver" paper which is used for the purpose you are investigating.

Dave Hillman
Rockwell Collins
[log in to unmask]

On Tue, Jan 23, 2018 at 6:04 PM, SALA GABRIELE <[log in to unmask]> wrote:

> Hello
>
>
>
> Please, could someone there explain me the difference , if there is 
> any, between Sulfur Free Paper and Acid Free Paper ?
>
>
>
> I am investigating about paper sheets interposed between PCB  (ENIG 
> and ImAg
> finisch) when piled up for packaging and shipping.
>
>
>
> Many thanks
>
>
>
> Gabriele
>
>
>
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