People often pick up a plastic bag and use it to hold food, but they do not know that this is very harmful to human health. For example PVC plastic is toxic. Although polyvinyl chloride resin is non-toxic, in the process of manufacturing plastics, the added plasticizer is toxic, and the added stabilizer is also toxic. Therefore, when packaging food, special food packaging bags must be used, and must not be used indiscriminately. The following points should be paid attention to during use:1.When PVC products come into contact with solvents such as ethyl ether, lead salts will be precipitated, so it is not suitable to store alcohol-containing food in PVC plastics.2.When polyvinyl chloride plastic encounters oily food, the lead in it will dissolve into the food, so it is not suitable.3.The use temperature of PVC plastic is higher than50℃, it will slowly releaseHCIGas, which is very harmful to human health.4.bakelite(Bakelite)and electric jade(Urea formaldehyde plastic)When used at high temperature, harmful free monomers, phenol, formaldehyde, urea and other toxins will be produced, and it is not suitable for food packaging and containers.5.Waste plastic recycling products, due to the complex source of raw materials, inevitably contain toxic components, so it is not suitable for use as food packaging.People’s daily packaging plastics are generally free of additives, such as polyethylene and polypropylene. Food bags, oil drums, fast food boxes, etc. made of these materials are non-toxic.How to identify whether it is toxic in commonly used plastic products??There are many methods of identification, such as appearance method, specific gravity method, boiling water method, combustion method, etc. The relatively simple and accurate method is the combustion method. The introduction is as follows:Cut a strip of the sample, hold it with tweezers, and burn it on a lit alcohol lamp(Lighted candles can be used instead of alcohol-free lamps), and then observe the difficulty of burning, the situation after leaving the fire, the flame and smoke color, the phenomenon during burning and the smell emitted, etc., and make a comprehensive judgment to know what kind of plastic it is.Polyvinyl chloride plastic: non-flammable, extinguished immediately after leaving the fire, the flame and smoke are green at the bottom and yellow at the tip, and there is a pungent smell of hydrochloric acid gas after the fire is extinguished.Polyethylene plastic: flammable, after-burning from fire, flame and smoke-colored bottom blue top yellow, continuous dripping of molten material when burning, giving off paraffin odor.Polypropylene plastic: flammable, after-burning from fire, the flame and smoke are orange-yellow, and there are continuous drops of dissolved substances when burning, and there is a petroleum odor.Polystyrene plastic: flammable, after-burning from fire, orange-yellow flame, black smoke, black carbon powder flying into the air, styrene odor.Bakelite(bakelite): It is incombustible, extinguishes immediately after leaving the fire, the flame turns yellow, expands and cracks when ignited, and emits a pungent smell of phenol.Urea formaldehyde plastic(electric jade): It is incombustible, extinguishes after leaving the fire, the flame color turns yellow, when it is ignited, it expands with cracks, and emits a pungent urea odor.
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