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 +3O_2
>2P_2 O_3 , 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
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