After sweating in the playground, when you pick up the sports water bottle to drink, do you notice a triangle sign at the bottom of the cup, a number in the triangle. Many people know that this number is a plastic recycling mark, representing the classification of plastic material, but this number specifically represents what plastic, and what is the characteristics of the plastic, perhaps it is rare to accurately answer it.

The small triangular symbol is usually printed on the bottom of the plastic container. It is like the identity card of the plastic container, and the numbers from 1 to 7 represent the type of resin used.1 is PETE, 2 is HDPE, 3 is V, 4 is LDPE, 5 is PP, 6 is PS, and 7 is other species.

PETE or writing PET, the chemical name is polyethylene terephthalate , commonly used in mineral water bottles, carbonated beverage bottles, mobile phone film and other products, for disposable products, throw away. More than 70℃ PET is easy to deform, and will release toxins, not recycled hot water, can not be put in the car in the sun, also can not hold wine, cooking oil; used after 10 months, may release carcinogen DEHP (use plasticizer in products), not recommended for food, toxic oh! Therefore, the beverage bottle is used up to throw away, do not be used as a water cup, or used to do a storage container to hold other items, so as not to cause health problems and the loss.

HDPE also writes PE-HD, the chemical name is high density polyethylene, commonly used in plastic food bags, shopping bags, washing bottles and other products, waterproof and chemical resistance, but its surface is difficult to clean, easy to breed bacteria, it is not recommended to recycle in food and drugs. Warm reminder: 4L bottle of Nongfu Spring water bottle (see the picture below) is marked at the bottom as 02. Although the large bottle looks much stronger than the general mineral water bottle, but it is not recommended to hold water, the possibility of long-term use of harmful substances is very large.

V or writing PVC, the chemical name is polyvinyl chloride, excellent plasticity, cheap price, so it is very common, often used in raincoat, socket, water pipes, credit cards and other products. Can only withstand heat 81℃, high temperature is easy to produce bad substances, do not belong to food grade materials, do not contact with food, if the drinks do not buy. Difficult to clean easy to residue, do not recycle.

LDPE also writes PE-LD, the chemical name is low density polyethylene (Low-Density Polyethylene), commonly used in plastic wrap, toothpaste and other products. At 110℃ will appear hot melting phenomenon, produce harmful substances, with food into the human body, may cause breast cancer, newborn birth defects and other diseases. Plastic wrap is not recommended for heating in the microwave oven.

PP chemical name is polypropylene, which is often used in plastic boxes, lunch boxes, plastic water cups, milk bottles and other products. PP melting point up to 167℃, with heat resistance and chemical resistance, can be appropriately used for microwave heating. Poor transparency, and can be reused after careful cleaning. Only PP can only be put into the microwave oven heating, the other can not oh! It should be noted that some microwave oven boxes are made with no. 5 PP, but the box cover is made with no. 1 PET. Because PET cannot be offset against the high temperature, it can not be put into the microwave oven together with the box body.

The PS chemical name is polystyrene, which is often used in foam packaging box, instant face box, foam packaging materials and other products. PS in strong acid, strong alkali will produce toxins, avoid packaging temperature is too high food oh. Can not put into microwave oven, lest because temperature is too high and release chemical, the bowl of PS material with instant noodles is not scientific not professional!

OTHER refers to other kinds of resin, common kinds of polycarbonate vinegar (PC), styrene-propylene eyeball copolymer (SAN), etc., commonly used in the kettle, water cups, milk bottles and other products. Now a little high-grade kettle is made of it, such as web red “ton bucket” (see below), some businesses often use such materials of water cups as gifts. Their respective health factors vary according to the material, and the PC is easy to release the toxic substance bisphenol A, which is harmful to human body, do not heat up, do not bask directly in the sun.

The number of 1-7 not only shows the characteristics of plastic materials, and helps us to use them reasonably and safely in life, but also simplifies the difficulty of identifying waste plastic categories in the process of physical recycling. Physical recycling (PCR Mechanical) refers to the recycling method of waste plastics directly used for molding and processing after sorting, cleaning, crushing, melting and granulation. At present, it is mostly used for treating PET, PE, PVC and other waste plastics. Physical recovery uses the existing infrastructure to reduce the greenhouse gas footprint, and is the most efficient carbon recovery method. However, physical recycling has limitations to the recycling of plastic waste, which is limited to clean sources. Most of the recycled plastic waste, the quality and performance will be degraded, and eventually all become waste, or even cannot be recycled at all. Therefore, in order to cope with the challenge of plastic waste and build a circular economy, it is necessary to adopt a combination of physical recycling and chemical recycling strategies.

Chemical recycling is an effective supplement for physical recycling, is also a kind of advanced recycling technology, it will waste plastic polymer chain into monomers, recycling value is not high or cannot physical recycling material will not reduce the product quality, can make recycled material reproduce high quality performance, can again and again to recycling use polymer, realize the high value of waste plastic utilization and the real circular economy. Chemical recycling can not only recycle more waste plastic, but also reduce the dependence on fossil fuels, protect the environment, promote material regeneration, solve the crisis of plastic pollution, but also reduce carbon emissions. It has many advantages, but due to the diversification of chemical recycling technology routes and the economic problems of business models, there are still many bottlenecks in its development.

We hope that we can reasonably use plastic products including water bottles and lunch boxes in our life, innovatively recycle plastic waste in production, help circular economy with new solutions, build new materials, and create a better environment!

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