Here's a good article focused on component reliability with some discussion of how red phosphorus is produced and comparison to several alternate fire retardant chemistries:
https://www.dfrsolutions.com/red-phosphorus-induced-failures-in-encapsulated-circuits Cheers, Adam in Atlanta [email protected] On Tue, Jan 1, 2019 at 5:46 PM John Woodgate <[email protected]> wrote: > Well, there wouldn't be any mention of white phosphorus, of course, > because that would indicate that the technique is not safe at all. I just > wonder how they stop it happening; it appears to be just a mechanical > envelopment by the polyamide (e.g. Nylon). If so, prolonged moderate > heating over several years might cause migration and subsequent conversion > to the other allotrope at surfaces. > > The BASF document is quite informative: > *In a report by the German Federal Environment Agency, it is stated that > the red phosphorus used in polymers can only be released into the > environment at the plastic interfaces, where it reacts with water to form > phosphorus oxides and** phosphoric acids.* > > Actually, it's a two-step process; first we get oxidation: 4P +3O2 >2P2O3, > then the trioxide dissolves in water to make 'phosphorous acid' (the quotes > are because it exists in two forms with different formal chemical names). > > I just hope that this isn't another case like CFCs, where a highly > undesirable effect was not recognized until it became serious. The > Wikipedia article on allotropes of phosphorus says: > > *However, for electronic/electrical systems, red phosphorus flame > retardant has been effectively banned by major OEMs due to its tendency to > induce premature failures. There have been two issues over the years: the > first was red phosphorus in epoxy molding compounds inducing elevated > leakage current in semiconductor devices[5] and the second was acceleration > of hydrolysis reactions in PBT insulating material.* > > I think that's a wrap! > > Best wishes > John Woodgate OOO-Own Opinions Only > J M Woodgate and Associates www.woodjohn.uk > Rayleigh, Essex UK > > On 2019-01-01 21:24, Richard Nute wrote: > > > > If the hype is true, and my interpretation is correct, red phosphorous as > a flame-retardant additive is much better than bromine-based additives. I > don’t know of cost differential. (In the two websites I looked at, there > was no mention of degradation to white phosphorus.) > > > > BASF: > https://www.plasticsportal.net/wa/plasticsEU~en_GB/function/conversions:/publish/common/upload/technical_journals/electronics_and_mechatronics/Umwuchtsensor.pdf > > > > Rinka: http://www.rinka.co.jp/english/products/flame-retardant/index.html > > > > Best wishes for the New Year, > > Rich > > > > > > > > > - > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to < > [email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > > - > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to < > [email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
