From the principle of thermal insulation, the thermal insulation performance of the thermos cup is mainly achieved through the close cooperation between the cup body and the cup lid. When hot water is put into the thermos cup, it is difficult for external heat to pass through the gap between the cup body and cup lid, thereby slowing down the heat loss and allowing the hot water to remain warm for a longer period of time.
From the perspective of plastic materials, different plastic materials have different thermal conductivity and insulation properties. Some high-quality plastic materials, such as PP, PC, etc., have good thermal insulation properties and can effectively prevent the transfer of heat. Therefore, if the plastic cup lid is made of these materials, its thermal insulation performance will be relatively good.
From the perspective of product design, the lid and body of the thermos cup generally adopt an integrated design or a closely matched design to reduce the channels for heat transfer. For example, some thermos cups will add a layer of sealing ring inside the cup lid to enhance the heat preservation performance. Some thermos cups with loose lids and cup bodies may suffer from heat transfer, resulting in a decrease in insulation performance.
To sum up, whether a plastic cup cover will affect the heat preservation performance of the cup mainly depends on the comprehensive effect of multiple factors such as plastic material, heat preservation principle and product design. If the plastic cup cover is made of high-quality thermal insulation material and fits closely with the cup body, its impact on the thermal insulation performance will be relatively small. However, if the product design is unreasonable or the plastic material used is not suitable for thermal insulation, then it may have a certain impact on the thermal insulation performance. Therefore, when choosing a thermos cup, consumers should pay attention to choosing products with high-quality materials and reasonable design.