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Flame retardants in electronics:
Are halogen-free alternatives the future?
Stephanie Dalquist
14 May 2002
Introduction of flame retardants
• Consumer use since 1930’s
• 300,000 tons of brominated FR in 1998
– 6,000 tons alone in European household electronics
• Most contain bromine or phosphorus
• Newer organic alternatives
– Less effective and more expensive
– More environmentally friendly?
– Fewer health risks?
Why flame retardants?
• Significant fire damage worldwide
– 12.9 billion in the US annually (1% GDP)
– 425,000 fire incidents
– 4,000 deaths and 26,000 injuries
• Delayed or suppressed ignition
– Reduce damage, prevent spread
– Slow evolution of toxic gases, factor in 80% of
deaths
• Save 290 lives in the US annually
Driving forces of change
• Legislative
– European Union eliminates PBDE and PBB by 2004,
all brominated retardants by 2008
– Japan considers legislation
• Environmental and worker concerns
– Sweden’s TCO
– Large buyer guidelines
• Public Perception
– Dioxins and furans in human blood, breast milk
– Increased value seen in green products
Types of flame retardants
• Reactive
– Chemically bound to polymer
• Cannot evaporate, migrate through polymer
• Alter polymer properties, increasing cost
• TBBA
• Additive
– Small molecules in PVC, PS, polyester
• More effective
• More evaporation, can penetrate tissue
Toxicity of flame retardants
• PBDE decompose to PBDD, PBDF
– Public fear of dioxins and furans
• TBBA fairly safe
– Low acute toxicity
– Dioxins and furans in rare circumstances
• Increasing MSW from 8% to 27%, no changes
• At low temperatures, yields up to 10%
• Halogen-free compounds decompose to
relatively benign aromatics
Performance of halogen-free retardants
• Available for all key electronics applications
• Laminates for PWBs
– Pass peel strength, pressure cooker tests
– Few compare in surface insulation resistance
• Additive loading up to 30% to meet V0
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Brominated loading around 6-10%
Alter polymer curing kinetics
Reduce peel strength
Increase moisture adsorption
Reduce electrical properties
Performance of halogen-free retardants
• Substitution occurs regardless
– Voluntary or as a result of legislation
– Unable to meet V0 standards
– Requires costly changes to manufacturing
processes
– Challenges established product reliability
Conclusions
• European Union has made the right move
by phasing out PBDE
• Push to eliminate all halogenated FRs is
extreme, based on available data
• Halogen-free technology not comparable
for fire safety
• Substitution with safer FRs like TBBA until
new FRs fully developed