Correct use of the hottest fresh-keeping film

2022-08-13
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How to use fresh-keeping film correctly

what kinds of fresh-keeping film are there

there are three kinds of fresh-keeping films in China's domestic market:

the first is polyethylene, or PE for short. This material is mainly used for food packaging, such as household fresh-keeping films sold on the market

the second is polyvinylidene chloride, PVDC for short. It has good oxygen barrier and long preservation time. It is mainly used for the packaging of cooked food, ham and other products. However, the price of this kind of material is relatively high and the manufacturing process is difficult, so there are few such fresh-keeping films on the market

the third kind is called polyvinyl chloride, or PVC for short, which is processed by adding a large amount of plasticizer (DHEA) and other additives to PVC resin. This kind of fresh-keeping film is mostly used in supermarkets to purchase and package food. PVC fresh-keeping film has good transparency, is not easy to crack, has good viscosity, and the price is low

therefore, it can be concluded that the household fresh-keeping film purchased in the supermarket can be safely used because it is basically made of PE (consumers find signs such as "PE", "no PVC" or "can be used for microwave heating" on the fresh-keeping film when purchasing goods)

pvc fresh-keeping film is a toxic film

pvc really so terrible? Experts pointed out that PVC itself is not toxic. Under normal conditions, PVC will not cause harm to human body. In fact, the important requirement for the application of PVC in our daily life, especially the high stiffness precision spring, is that the testing accuracy of the equipment is very wide. For example, blood bags and infusion tubes are made of PVC. If PVC has toxic effect, it will not be used in medical devices

experts from China Plastics Processing Industry Association said: PVC releases harmful substances only after heating in microwave oven or packaging overheated and oily food. PVC is a high polymer with relatively stable properties. Only when it is heated until its plastic properties are destroyed, it can accurately obtain the data of the tested object before it releases hydrogen chloride, causing harm to the human body. As for whether the chlorine contained in PV, as a degradable material, decomposes into water and carbon dioxide C causes cancer and how harmful it is to the body, an expert from the Technology Development Department of China Packaging Technology Association said that at present, there is no scientific test basis to draw specific conclusions

it is worth noting that the higher the temperature of all plastic products, the worse the thermal stability, and it is easy to release the main operating principle or gas of the impact testing machine. Therefore, for the sake of safety, all fresh-keeping films should not be heated in the microwave oven together with food

how to distinguish PVC and PE

at present, many supermarkets in Beijing have said that they do not use PVC fresh-keeping film, or no longer use PVC fresh-keeping film. However, many supermarkets still use PVC fresh-keeping film

when shopping for food packaged with plastic wrap, consumers can distinguish PE and PVC plastic wrap by themselves. PE plastic wrap has poor viscosity and transparency, and it is easy to open after rubbing by hand; While PVC fresh-keeping film has good transparency and viscosity. It is not easy to unfold after rubbing with hands, and it is easy to stick to hands; The taste of PE fresh-keeping film is light, with a candle smell, and the taste of PVC fresh-keeping film is heavy; After burning, the PVC fresh-keeping film will have obvious traces of charring, but the PE fresh-keeping film does not

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