Why can only stainless steel water bottles be used as thermos cups

What is a thermos cup? Are there any strict international requirements for thermos cups?

As the name suggests, a thermos cup is a water cup that preserves temperature. This temperature represents both hot and cold. It means that the hot water in the water cup can be kept hot for a long time, and the cold water in the water cup can be kept cold for a long time. There are international definitions and regulations for thermos cups. Pour 96 degrees Celsius hot water into the cup, seal the lid tightly and let the cup stand. After 6-8 hours, open the lid and test the water temperature to be 55 degrees Celsius. It is a qualified thermos cup. Of course, this regulation was proposed many years ago. With the continuous improvement of production technology and processes, some thermos cups can even be kept warm for 48 hours through changes in product structure and processes.

How can a water cup have good thermal insulation performance?

At present, global unification is still achieved by using a vacuuming process, which is to extract the air in the original double-layer cup interlayer to make the interlayer think of a vacuum state, thereby preventing the physical phenomenon of heat conduction, so that the water temperature in the cup will not be lost. so fast. Please note that the editor said that it will not drain so fast because although the wall and bottom of the water cup are double-layered, the mouth of the cup must be open, and most cup lids are not metal. When vacuuming, the heat rises and the temperature is lost from the mouth of the cup.

The vacuuming process requires a vacuuming furnace, and the temperature in the furnace is as high as several hundred degrees Celsius. Obviously, a double-layered water cup made of plastic material will melt and deform at such a temperature. Ceramics can withstand such temperatures, but because the interlayer air pressure after vacuuming is greater than the ambient air pressure, the ceramics will explode. There are also some materials such as silicone, glass, melamine, wood (bamboo), aluminum and other materials that cannot be made into thermos cups for this reason.

Therefore, only qualified metal materials that meet food-grade requirements and have a strength similar to stainless steel can be used to make thermos cups, and other materials cannot be made into thermos cups.