Guenter

It is not just bromocarbons you should examine. Most epoxies contain a certain
quantity of sodium chloride. The basic prepolymerisation supplies the epoxy group from
epichlorohydrin in its reaction with bisphenol A and the bromophenols. This is done
with some sodium hydroxide present, so that the chlorine atom is lost to the sodium
atom, leaving the epoxy group free to react during the subsequent cross-linking. Much
of the NaCl is removed but a certain quantity always remains. This is why epoxy resins
have a high dielectric constant and a poor power factor at high frequencies. There are
a few expensive speciality epoxies which do not use this particular prepolymerisation
reaction and therefore no NaCl.

Brian

Guenter Eckart wrote:

> Dear all,
> we are, together with the lead-free actions, also working on
> halide-free systems. With regard to semiconductor packaging (OFP, PLCC
> etc. - epoxy mould compound) what is the halide content of the commonly
> used flame retardants.
> Who has a reliable number?
> Thanks for your help.
>
> Guenter Eckart
> Alcatel SEL
>
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Assemblies.
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(http://www.leadfree.org ) for additional information.
For technical support contact Gayatri Sardeshpande [log in to unmask] or 847-790-5365.
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