55-degree constant temperature coaster may be a new taste. Generally, this possibility is related to the fact that the cushion of the thermos cup is rubber and the sealing ring is rubber. Can be used for a period of time, no smell.

It is possible that the material of the heating pad you use is not very good. You can consider changing to a good one.

Pay attention to whether the product is qualified: whether the accessories used are healthy and environmentally friendly. Whether the plastic part of the insulating coaster is healthy and environmentally friendly is very important.