I am trying to make rubber underlay, it has silver foil on one side and felt on the other, the middle part is rubber sheet, it turns to rubber crumbs if we remove it, we are not able to understand if it is rubber or plastic as after burning it becomes hard and turns into ashes, these type of sheets are made in china only and we need to understand how are they made, so if someone has some knowledge about it please share it, these sheets are used in flooring.