PLA continuous operative temperature
EvilTeach's answer is correct, ABS is a more reliable plastic for any kind of work which may get above what feels "hot to the touch." 

Just to elaborate on the why: the property you're looking for in the thermoplastic (which will determine the continuous operating temperature) is glass transition temperature. This is the point at which the plastic begins to flow, and becomes deformable as EvilTeach described. PLA reaches this state at around 60&nbsp;°C, whereas ABS is around 105&nbsp;°C, just suiting your specifications. To go a bit further, polycarbonate offers a glass transition temperature of around 150&nbsp;°C, and Ultem at 217&nbsp;°C. So there's a thermoplastic for everyone, you just need to know what you're looking for!