dear All, I'm looking for a plastic that can be thermoformable or injected, that can withstand let's say 100°C I feel that this heat resistant is opposite to thermoformable behaviour? And injection? Have any suggestions about which polymer are able to withstand this temperature without getting yellow?
Glass
PMMA, PC, HT-PC to name a few ...
It all depends for how long it has to withstand 100=B0C Do you expect to withstand for several hours or forever ... ?
"Glass" schrieb im Newsbeitrag = news:bf5lhs$8dc$ snipped-for-privacy@atlantis.cu.mi.it...
behaviour? And
100°C how long, which preassure, which chemical resitance is needed?
I think HDPE is in that range, but take a simple PA, normaly it will work...
Take PPS PEK or PEEK and you are far away from 100°C
A TPU? most good types will work with 100°C, but to be sure take a PPDI or TODI Type...
100°C is nearly nothing....POM will also work, diffrent Polyesters (PBT 30% glasballs...)
without getting yellow? take a black one ;-) PA 46 with 30% Glassfibers..
What is your application?
Michael I am not a bug I am a undocumented feature
High density polyethylene (HDPE) is most likely your least expensive choice. Most grades do not soften appreciably until you reach temperatures around 125 C. It is also readily processed in a number of manners - extrusion, thermoforming, blow molding and injection molding. Polypropylene (PP) is the next choice (Tm ~ 160 C). It can be injection molded quite easily, but thermoforming can be tricky. You may need to add an olefinic elastomer such as DuPont Dow Elastomer's Engage® product or an EPDM rubber to build enough melt strength for thermoforming.
The antioxidant package that comes with both HDPE and PP is typically good enough to prevent yellowing during processing. However, if they are going to be exposed to 100 C for a prolonged period, you may want to add some additional antioxidant to them.
Larry Effler
Glass wrote:
Let's say that the thermal cicle is of a lamp, so it could be a daily working period of 7/8 hours winter/autmunn, and 5/6 hours in summer/spring, no high pressure and no agressive chemicalsv around
A lamp
ok, but then:
have you measured the 100°C?
a good chemicist can hold cooking water....
but I never change a hot lamp.... (ok I am a physicsit ;-))
But for your problem there was an article in a BAYER Publication during the last year
and I think it was the guy of TER HELL who was proud of a solution...
And last year I heard about a transparent adhesiv for that application made by DELO
.....
so contact this guys, perhaps they have the solution of your problem...
(BTW the problem with the yellow colour may be more worse with Hg Lamps... without Temperature problems...
so the
"use a black polymer" was not the badest advice...
Michael I am not a bug I am a undocumented feature
In this case you should consider:
PC like Macrolon=AE from BAYER or HT-PC like Apec=AE* also from BAYER or PES / PSU like Ultrason=AE from BASF or ...
All those plastics are being used for this kind of application and those plastics can take the heat. I am assuning here that=20 you need a glossy surface appearance and perhaps even metallizability, which again would be ok for those resins.
If your application is "only" a lamp housing, for which high gloss is usually not needed, you can use lots of other resins. A good choise might be mineral filled PA 6 or PA66.
As process you ought to consider injection molding and not=20 thermoforming, in my opinion, because this will give you much more material options. Thermoforming is normally (there are exceptions !)=20 related to amorphous resins which are relatively expensive when good=20 long term heat resistance is needed as well, compared to = semi-crystalline=20 injection molding grades.
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