Question about Bismuth presence (as contaminant) in injection mouldsurface, after injectin...

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Gino Ferrero's Avatar (by Gravatar) posted on
June 30, 2011, 6:10 am
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Dear fellows,
one of my customers find Bismuth (yellow powder) on injection moulds
surface after injecting PP.
I've been asked about the possible origin of such contamination:
Any idea ?
Thanks

Gino Ferrero

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Ernie's Avatar (by Gravatar) posted on
June 30, 2011, 3:29 pm
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Re: Question about Bismuth presence (as contaminant) in injection mouldsurface, after injecting PP



Does the PP contain a fire retardant?  Has the customer mixed in some
regrind?

Ernie


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Gino Ferrero's Avatar (by Gravatar) posted on
June 30, 2011, 4:23 pm
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Re: Question about Bismuth presence (as contaminant) in injection mouldsurface, after injecting PP

Il 30/06/2011 21:29, Ernie ha scritto:

Yes, the PP was partially regrind.



 
RolfWissmann's Avatar (by Gravatar) posted on
July 1, 2011, 11:16 am
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Re: Question about Bismuth presence (as contaminant) in injection mouldsurface, after injecting PP


Does your PP contain a "Radiopacifier" based on Bismuth Trioxide

http://biomerics.com/additivetechnologies
http://www.cheap-chemicals.com/chemicals.asp?Sort=B

which partially ends up as a mould deposit?

If so, perhaps the molding conditions need to be adjusted
(less shear, lower temperatures, kitchen sink, etc. ...)


 
Stewart's Avatar (by Gravatar) posted on
July 5, 2011, 8:30 am
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Re: Question about Bismuth presence (as contaminant) in injection mouldsurface, after injecting PP


If bismuth trioxide is compounded into the resin and it is showing up
as residual on the processing equipment, one should also go back to
the compounding process.  There are numerous issues that can be
created in the compounding of radiopaque fillers, and the bismuth
trioxide can on of the more problematic ones.


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