Most of the plastic wrap and commonly used plastic bags sold on the market are based on vinyl masterbatch as raw materials, according to the different types of vinyl masterbatch, plastic wrap can be divided into three categories.
The first is polyethylene, referred to as PE, this material is mainly used for food packaging, we usually buy back fruits, vegetables with this film, including the semi-finished products purchased in the supermarket are used in this material;
The second is polyvinyl chloride, referred to as PVC, this material can also be used for food packaging, but it has a certain impact on the safety of the human body;
The third is polyvinylidene chloride, referred to as PVDC, which is mainly used in the packaging of some cooked food, ham and other products.
These three kinds of plastic wrap, PE and PVDC of these two materials of plastic wrap is safe for the human body, can be assured to use, and PVC plastic wrap contains carcinogens, greater harm to the human body, therefore, in the purchase of plastic wrap, should choose PE plastic wrap.
From a physical point of view, the plastic wrap has moderate oxygen permeability and moisture permeability, regulating the oxygen and moisture content around the fresh-keeping products, blocking dust, thus extending the freshness of food. Therefore, it is necessary to choose different plastic wrap for different foods.
The plastic wrap on the market is roughly divided into two categories, one is ordinary plastic wrap, suitable for refrigerator preservation; One is microwave plastic wrap, which can be used for both refrigerator preservation and microwave oven. The latter kind of plastic wrap is far superior to ordinary plastic wrap in terms of heat resistance and non-toxicity. Therefore, consumers should pay special attention to the use of choice, itemized use.