What material is the liner of the ice cube container in the hotel made of?

Double glazing.

The inner tank of the thermos pot is made of double-layer glass. A thermos bottle/kettle is an insulated container made of a double-walled bottle with a vacuum inside as the inner liner and a outer shell. It is a very common daily necessities.

The outside of the thermos flask has a shell made of bamboo strips, iron sheets, plastic, etc., with a bottle bladder inside. The bottle bladder is made of double-layer glass. Both sides of the interlayer are plated with silver and other metals, and the middle is evacuated. There is a stopper at the mouth of the bottle, which can maintain the temperature inside the bottle for a long time. Those that hold hot water are usually called thermos bottles; those that hold cold food are usually called ice bottles. The concept of a thermos flask is simple: the bottle has an inner wall and an outer wall; there is a vacuum between the two walls. Heat conduction and convection cannot occur in a vacuum, and the plated metal reflective layer can reflect thermal radiation. Therefore, any liquid poured into the bottle can maintain its original temperature for a long period of time.