How to test the vacuum cup

1. See thermal insulation performance. The main function of the thermos cup is to keep warm. We just need to fill the thermos cup with hot water, tighten the lid, and touch the outer surface of the cup, especially the bottom of the cup, after 2-3 minutes. If the body and bottom of the cup are hot, it means that its inner liner is not vacuum and its thermal insulation performance is poor.
2. Check the tightness. When selecting a cup, you can fill the cup with water, tighten the lid, turn it upside down for 10 minutes, or shake it vigorously. If there is no water seeping out, it means that the sealing of the cup is good.
3. Look at the material. Whether the cup cover is made of food-grade plastic, and whether the leak-proof rubber ring is food-grade silicone. This material is safe and non-toxic, has no peculiar smell, smooth surface and long service life. On the contrary, ordinary plastic materials have a strong smell, are prone to aging and fracture, and will also affect the health of water quality. Whether the cup body is made of 304 stainless steel. 304 stainless steel has excellent quality, corrosion prevention and rust prevention, bright color and health protection. Other materials of stainless steel have the problem of excessive manganese content, which will lead to unstable steel performance, easy to rust and corrosion, and long-term contact with the mouth is easy to lead to excessive metal content in human body.