How to identify commonly used plastic packaging products?

Daily packaging plastics generally do not add additives, such as polyethylene and polypropylene. Packaging products such as food bags, oil drums, and fast food boxes made of these plastic materials are non-toxic. How to identify whether common plastic products are toxic? There are many identification methods, such as the appearance method, specific gravity method, boiling water method, combustion method, etc. The simpler, easier, and more accurate method is the "combustion method". The introduction is as follows:

Cut a strip of the plastic bag sample, clamp it with tweezers, burn it on a lit alcohol lamp, and then observe the difficulty of burning, the situation after leaving the fire, the color of the flame and smoke, the phenomenon during burning and the smell, etc., and finally conduct A comprehensive judgment will tell you what kind of plastic it is. The specific judgment criteria are:

1. Polypropylene plastic: It is flammable and will ignite after leaving the fire. The color of the flame and smoke will be orange-yellow. When burning, there will be constant dripping of dissolved substances and a petroleum smell.

2. Polyethylene plastic: It is flammable and will ignite after being removed from the fire. The color of the flame and smoke will be blue at the bottom and yellow at the top. When burning, molten material will continue to drip and emit a paraffin smell.

3. Polyvinyl chloride plastic: It is non-flammable and extinguishes immediately after leaving the fire. The color of the flame and smoke is green at the bottom and yellow at the tip. There is a pungent smell of hydrochloric acid gas after the fire is extinguished.