Nowadays, paper takeout boxes are becoming increasingly popular and are commonly used for foods like pizza and burgers. They are also widely used by Chinese restaurants in the United States. Some consumers have raised concerns about the smooth, slippery coating inside these paper boxes, wondering if they are waxed. In fact, this slippery layer is a plastic film known as a "polyethylene coating."
Ruan Guangfeng, a master of nutrition and food safety and a science writer, explained in his article that "polyethylene coating" is a relatively new process. During the molding process, a thin polyethylene plastic coating is applied to the paper surface, essentially creating a plastic film that covers the paper. This allows paper takeout boxes to withstand temperatures of up to around 90°C and provides excellent water resistance, making them suitable for packaging food as well as holding cold and hot beverages.
However, these paper boxes cannot handle higher temperatures, so it is not recommended to use them directly in a microwave for heating.