"Well ABS should be fine too - it is said to have a melting point of 200C.
All of these plastics seem to be able to stand up to any amount of steam you want to throw at them, and if you want to do it under pressure, so much the better."
When designing plastic parts, we usually don't look the melting point but the HDT value (heat deflection point). https://omnexus.specialchem.com/polymer-properties/properties/hdt-1-8-mpa-264-psi
When you want to inject a plastic part with very thin walls, you have to select a very fluid material. Then yes, the most suitable fluid material is PP (polypropylene) and very cheap. The problem with this material is that it is very soft and deformable under heat, it is also one of the weakest (50°C). PP is often used in automotive parts and stand high temperatures but in this case mineral or glass fibbers are added to the polymer at ratio going up to 40 or 50%. But then, forget the fluidity and injection of thin walls (cells).
ABS (Acrylonitrile Butadiene Styrene mix) or PS (polystyrene) is a better candidate with the advantage that surface tension is higher and that queen is able to stick its eggs in the bottom of the cell, which I doubt it could be possible with PP. But HDT is still too weak to support steam under pressure with HDT 85°C. Frames are designed for use in a hive at room temperature or normal temperature under the roof of hive but not to be sanitised with steam. In case you want to eliminate bacteria, fungus or spores, you have to use bleach or potassium hydroxide.

Georges France
PS : to all who received message using my name asking for money, I claim that I have never been sick 

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html