Re: At what temp F does tupperware begin to melt?

Tupperware is made from high density polyethylene [HDPE] and depending on 
several other factors, will melt at around 278 F [137 C].

The melting point of polymers like HDPE is not like ice melting to water --  
which is indicative of a sharp phase change. Plastics, instead, undergo 
transitions from one physical form to another. 

For HDPE it is 'frozen' and brittle at temperatures below about -184 F [-120 
C]. Between there and its melting point, it is in its plastic zone where it is 
tough and flexible. Above the melting point it becomes a viscous fluid, which 
allows it to be processed and fabricated into things like Tupperware and gallon 
milk jugs.