Increasing hardness of physically foamed PS profiles
Increasing hardness of physically foamed PS profiles
(OP)
I'm currently searching for a way to make our profiles harder and (if possible) cheaper. Current density is about 250 kg/m³, durometer hardness 22-25 Sh.D.
The obvious way is to use some kind of mineral filler. Preliminary tests have shown that both talcum and calcium carbonate can be dosed up to about 20% without deteriorating the quality too much. Oddly enough we see no increase in hardness. On the contrary, the hardness significantly decreases with added mineral filler.
I suspect this has everything to do with the structure and size of the foam cells, but exactly how the filler affects this is not known to me.
So, two questions: does anyone have experience with a similar process?
Are there any other possibly useful filler materials? I will be testing with wollastonite soon, mica is ruled out because of the glitter.
The obvious way is to use some kind of mineral filler. Preliminary tests have shown that both talcum and calcium carbonate can be dosed up to about 20% without deteriorating the quality too much. Oddly enough we see no increase in hardness. On the contrary, the hardness significantly decreases with added mineral filler.
I suspect this has everything to do with the structure and size of the foam cells, but exactly how the filler affects this is not known to me.
So, two questions: does anyone have experience with a similar process?
Are there any other possibly useful filler materials? I will be testing with wollastonite soon, mica is ruled out because of the glitter.





RE: Increasing hardness of physically foamed PS profiles
Regards
Pat
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RE: Increasing hardness of physically foamed PS profiles
RE: Increasing hardness of physically foamed PS profiles
RE: Increasing hardness of physically foamed PS profiles
RE: Increasing hardness of physically foamed PS profiles
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
RE: Increasing hardness of physically foamed PS profiles
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
http://eng-tips.com/market.cfm
for site rules
RE: Increasing hardness of physically foamed PS profiles
Pat: Coextrusion has not yielded demonstrable results yet but the top layer should make our profiles much, much harder. I am more looking for a way to make them temporarily harder until the coextrusion route works out.
RE: Increasing hardness of physically foamed PS profiles
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
http://eng-tips.com/market.cfm
for site rules
RE: Increasing hardness of physically foamed PS profiles
I don't know what your Durometer hardness corresponds to, but this: http://benchmarkfoam.com/eps-properties/ shows EPS able to take 40 psi loads witn 10% deflection. With an additional coating, it might get close to MDF, but given the overall density requirement, that sounds like a difficult challenge, since the relatively low density region is bound to collapse under load.
EPS supposedly can be made up to 640 kg/m^3, which should be quite hard, but will probably not be as hard as MDF.
TTFN

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RE: Increasing hardness of physically foamed PS profiles
RE: Increasing hardness of physically foamed PS profiles
IRstuff: I did not know EPS came in such high densities; in that case we are talking about the same product as mine. I doubt whether TV casings really go as high as 600 kg/m³ but I might be wrong :)