A statement in the circle of friends has been widely forwarded: "try not to drink water from disposable paper cups. If you use it, soak it in the best selling glass for 5 minutes, then pour it out and use it again." However, the experts interviewed by the reporter said that this statement "has no scientific reason".

Yesterday afternoon, the author visited a large supermarket and several small supermarkets on Wencui Road in Shenyang, and found that there was a gap between the disposable paper cups sold by the two only in terms of packaging.

The paper cup bags sold in large supermarkets are tightly sealed, which not only indicates the thickened cold and hot cups, but also indicates the Executive Standards and main raw materials. The raw material of a brand paper cup is marked as "paperboard and polyethylene film without recycled raw materials", and the manufacturer's information and contact information are very detailed.

In a small supermarket on the street, the author found that the disposable paper cup packaging plastic is very fragile and thin, there are cracks at the blank holder, ash is put into the bag, and the information on the packaging bag is fuzzy. It is impossible to find the necessary information about the material, manufacturer and executive standard of the paper cup, but the price is cheap, about half of that of the large supermarket.

Liu Zheng, a second-class professor and doctoral supervisor at the school of materials, Shenyang University of technology, said that there are three types of disposable paper cups in China: cold drink cups, hot cups and ice cream cups. There are also three kinds of coating: wax coated cup, polyethylene film cup and double insulation Cup.

Paraffin coated cups are usually scraped off the inside with a knife. There are 8 kinds of paraffin in the world, such as No.52, No.54 and No.66. The melting point of No.52 paraffin is no less than 52 degrees, and so on. If you drink hot water from this kind of cup, the paraffin will indeed melt. Water soaks into the cup, causing it to soften and leak.

However, the qualified waxed paper cup tested by the quality supervision department uses food grade paraffin, and a small amount of intake will not cause harm to human body. If the unqualified paper cup is used, the wax coating may be non food grade paraffin coating, which has safety and health problems.

Liu Zheng said, disposable paper cup with boiling water for 5 minutes to reuse is no scientific reason. If it is a wax coated cup, it is easy to soften and leak. Moreover, the water temperature of 100 ℃ cannot be maintained within 5 minutes. Even if the paper cup is sterilized with high temperature, benzene, polycyclic aromatic hydrocarbons and other harmful substances in industrial paraffin will not decompose due to water temperature.