Hi Camille,
Yes, the epoxy resins used to make FR-4 printed circuit boards (which
account for over 90% of PCBs made today) use the common brominated flame
retardant, TBBPA (tetrabromobisphenol A). While early drafts of the EU
electronics directives called for substitution of TBBPA, that restriction
never made the cut and there are currently NO major legislative restrictions
on TBBPA in the EU or elsewhere (though a health risk assessment is
currently being conducted in the EU, the outcome of which may affect this
status). But for now, YES, a PCB with the brominated FR TBBPA is compliant.
Here is a nice concise fact sheet on TBBPA:
http://www.bsef-site.com/env_health/tbbpa/BSEF%20TBBPA%20Final.pdf
Also, my former employer, the Toxics Use Reduction Institute has some
excellent resources on brominated flame retardants
(http://www.turi.org/content/content/view/full/1966/) including the
following presentation on alternatives to TBBPA by Steve Scheiffers of
Motorola:
www.turi.org/content/content/download/1843/9558/file/scheiffers.pdf
Regards,
Todd
-------------------------------
Todd MacFadden
Component Engineer
Bose Corporation
The Mountain, Mail Stop 45
Framingham, MA 01701-9168
[log in to unmask]
voice: 508.766.9088
fax: 508.766.9057
-------------------------------
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Camille Good
Sent: Tuesday, January 11, 2005 3:39 PM
To: [log in to unmask]
Subject: [LF] Question about Halogen-Free PCBs
Dear list members,
Some of my colleagues and I have been receiving
contradictory information about halogen-free PCBs and
I was wondering if I could ask some basic questions to
the list.
1) We (meaning myself and the other engineers I work
with) have been told by our PCB supplier that they
don't have any halogens in their PCBs. But we do use
FR-4 and I have seen e-mails on some of the IPC lists
that seem to imply that all (or almost all) FR-4 PCBs
use halogen flame retardents. Is it indeed true that
all FR-4 PCBs use halogen flame retardents?
2) I also saw a comment on the lead-free list recently
that there are still some flame retardents (including
some commonly used in PCBs) that are halogen-based but
not banned by RoHS. So is it possible for our PCBs to
be RoHS compliant but NOT halogen-free?
3) My background is an MS in Electrical Engineering
and a couple of years working in the electrical
section at UL before I started working for my current
employer. So, while I can discuss UL PCB specs like
CTI and temperature and flammability ratings (like
V-0, V-1, etc.), I have very little knowledge about
the actual materials science that goes into PCBs. Are
there any good websites or books that anyone is
willing to recommend that will help me understand more
about the construction of PCBs, particularly actual
industry practices (like specific laminates, flame
retardants, soldermasks, etc.)?
Many thanks in advance for any assistance!
Sincerely,
Camille Good
Portland, Oregon
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