The material which can be deformed permanently by heat and pressure is called a thermoplastic.

Here's why:

* Thermoplastics are polymers that soften and become moldable upon heating, and solidify upon cooling. They can be repeatedly melted and reshaped without undergoing chemical change. This makes them ideal for things like plastic bottles, toys, and food containers.

Let me know if you'd like to know more about thermoplastics or other types of materials!