Halogen-free Materials FAQ
David Bedner, Principal Scientist at Isola, recently presented a webinar entitled, “Meeting Flame Resistance
Requirements for Green Electronics: Evaluating Halogen-free Materials” (http://video.webcasts.com/events/
pmny001/viewer/index.jsp?eventid=46152). The presentation explores the environmental impact of flame
retardants and the current trends in the industry and can help you to understand the trade-offs in selecting brominated
vs. phosphorus retardants to comply with today’s strict safety standards.
Below, please find the responses to the questions that were posed by the attendees. We hope you find this information
help and invite you to continue the conversation on our Facebook page at https://www.facebook.com/IsolaGroup
or email us at info@isola-group.com.
If there is such a small threat of dioxins and furans from
current brominated flame retardants, why still move to
halogen-free?
Are there any requirements for flame retardants that are
unique to your industry?
Two main requirements: Thermal reliability to stand up to the rigors
of soldering conditions and chemical resistance to survive etching
and plating operations.
It is market perception that being halogen-free is better for the
environment. Brominated ethers do generate copious amounts
of dioxins and furans and they are no longer used in electronic
applications. The “work-horse” brominated flame retardant is
TBBPA which has been proven safe many, many times over. The
one exception where people would prefer halogen-free FRs is
in transportation (bus, rail and plane) when if there was a fire, a
brominated FR would generated highly toxin HBr.
Are there other additive Br FRs with better thermal stability vs.
TBBPA? How do these compare with the higher decomposition
temperature observed with some of the Non-Hal materials?
Generally the Bromine is attached to an aromatic carbon whose
bond breaks at about 330C, some non-halogen FR decompose at
about 400°C.
Are there any advantages to non-Halogen flame retardants
over Brominated flame retardants?
Some halogen-free FRs have a higher decomposition temperature
than their halogenated counterparts.
Is the flame retardant material applied to the PWB, or is it
actually part of the laminate material?
It is part of the laminate material.
Can you speak more to the cost differences between the two
types of flame retardants?
Generally speaking on a pound to pound comparison of a
brominated FRs to non-halogen FRs the cost of bromine vs. nonhalogen/non-phosphorous FR is about 1:2, for a brominated FR vs.
a non-halogen/phosphorous based FR is about 1:6.
Are there any advantages to non-halogen flame retardants
over brominated flame retardants?
Higher decomposition temperature and non-halogen FR do not
generate HBr upon combustion.
Are there other testing methods used to evaluate materials
like glow wire ignition testing, hot wire ignition, and arctracking?
Can you speak to the new non-Halogen flame retardants
coming to market?
Unfortunately, the total market size of FRs that work in PWB is
a small fraction of the entire FR market. What we as electronic
material suppliers are left to do is find FR from other applications
and see if they can pass our requirements. Isola has started to
develop our own proprietary FR in house.
Our industry requires samples to pass a UL-94 flame test. Two
other popular test methods are heat flux and cone calorimeter heat
releases, both which are not currently required for our industry.
http://www.isola-group.com/product-category/halogen-free/
Halogen-free Materials FAQ
These tests seem to require materials that are different
than UL-94. Many customers are asking for materials that
pass multiple tests, are there a push in the industry to allow
materials to pass across these boundaries?
By and large no with the exception of some military applications
were they might require more combustion data.
Is there any electrical property differences between halogen
free fire retardants and halogenated FR?
By and large so far there is parity between the two types of FRs.
What toxicity and smoke density are being followed in
testing?
With the cost difference, does one work so much better for the
amount that you pay more?
No, for cost and performance Bromine is still the best choice.
Is there a difference in the weight for the two fire resistance
materials that you talk about, if it is a lighter material it would
have an advantage?
Generally speaking the non-Halogen FRs are less dense than their
Brominated counterparts, but the effect is greatly diluted once you
factor in the base resin system, fillers, fiberglass and the copper.
Our industry does not require this testing; some customers may
test this on their own.
What reactive halogen free molecules beyond DOPO are you
considering?
That’s proprietary to Isola, but rest assured we will test everything
we can find!
Looking for some reliability data on materials, long-term use
and feedback?
Bromine has been an established FR for the past 60 plus years.
There are a lot of published works recently for ‘synergists’
used to augment or lower the overall amount of brominated
FR. can you comment on the viability of still using brominated
FRs in this sense. Can it still be called “halogen free?”
Current IPC spec for halogens to be present in a non-halogen
laminate is combined Br/Cl of less than 1500ppm. That’s less than
0.15% FR, no FR is that effective.
ORDERING INFORMATION:
Contact your local sales representative or visit www.isola-group.com for further information.
Isola Group
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Phone: 480-893-6527
Fax: 480-893-1409
info@isola-group.com
10/2013
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No. 1 Hung To Road, Kwun Tong,
Kowloon, Hong Kong
Phone: 852-2418-1318
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D-52353 Düren, Germany
Phone: 49-2421-8080
Fax: 49-2421-808164
info-dur@isola-group.com
http://www.isola-group.com/product-category/halogen-free/