In everyday life we often see plastic are the following: polyester, polyethylene, polypropylene, high density polyethylene, low density polyethylene, polyvinyl chloride, polystyrene. In fact, these are our common "1-7" plastic.
PET: polyethylene terephthalate used to make water bottles, Coke bottles, juice bottles, screen protective film and other transparent protective film, usually colorless and transparent. Because it can heat to 70 ℃, so this only suitable for cold drink bottles and warm drink, put hot liquids (such as: hot water) or heating the deformation, there are harmful substances leaching; and the plastic products after using 10 months, may release carcinogenic, toxic to humans.
Advantages: high transparency, can see the contents of the bottle; acid, can be loaded carbonated drinks; waterproof high and difficult to bleed. Note: non-toxic, but the synthesis process may remain single, low molecular weight oligomers and side reaction products such as diethylene glycol, these are some toxic, PET raw material for beverage bottles countries have strict standards. Material PET plastic bottles can not be placed on the car sun; not install wine, oil substances, harmful substances that can dissolve it. Do not install more than 70 ℃ liquid, high temperature can cause the material decompose to release harmful chemicals.
HDPE: High density polyethylene suitable for loading food and medicines, equipment cleaning supplies and bath products, shopping bags, garbage cans, etc. At present, the use of plastic bags in supermarkets and shopping malls are mostly made of such material, can withstand 110 ℃ high temperature, indicating food bags can be used to dress the food. HDPE is widely used in a variety of translucent, opaque plastic containers, thick feel.
Advantages: relatively resistant to various corrosive solutions, and more are used in cleaning products, bath products. Note: The dress cleaning supplies, bath products bottles can be reused after cleaning, but these containers are usually not wash clean, the residual material will become a breeding ground for bacteria, it is best not recycling, especially in full bloom cycle is not recommended as the Food and Drug the container uses.
PVC: Polyvinyl chloride PVC is now used for the manufacture of some cheap leather, floor mats, water pipes, etc.; due to its good electrical performance has a certain self-retardant properties, is widely used in the manufacture of wire and cable sheath. In addition, PVC is widely used in industrial fields, especially for acid corrosion in high demand areas. Commonly used in: raincoats, PVC plastic pipe lines, water pipes, plastic switches, sockets
Advantages: high strength, resistance to climate change and better corrosion resistance. Note: this material can only heat 81 ℃, and therefore can not be used at higher temperatures. Is likely to precipitate toxic when used in the production of a large number of PVC plasticizers (plasticizing agents, such as DOP) and heat stabilizers containing heavy metals, and the synthesis is difficult to eliminate the presence of free monomers, and the high temperatures encountered in oil, carcinogenic so PVC in contact with the human body, especially in medicine and food applications, replaced by the PP, PE basically.
4, low-density polyethylene (LDPE)
Plastic film and plastic wrap, made of paper milk cartons, drink boxes and other packaging are using it as an inner foil. Utensils used for the plastic film, not as a beverage container. Commonly used in: cling film, plastic film, toothpaste or cleanser hose packaging. Pros: good ductility, use in life is extremely broad. Note: LDPE products at higher temperatures due to softening or melting, should avoid the use of higher water temperatures under 100 ℃. Cling film at temperatures above 110 ℃, there will melt and, therefore, the food placed before the microwave, first remove the cling film wrapped. 5, polypropylene (PP) microwave meal made using this material, resistant to 130 ℃ high temperature, transparency is poor, this is the only place in microwave plastic boxes can be reused after careful cleaning. PP high hardness and surface gloss. PP is also very broad range of use, everyday items such as packaging, toys, basins, buckets, hangers, cups, bottles, etc.; engineering applications such as car bumpers. PP spun yarn is known as polypropylene, textiles, non-woven fabrics, ropes, nets and other products are common.
Commonly used in: disposable juice, beverage cups, plastic plate, Lock & Lock crisper and so on. Pros: good air permeability, heat temperature up to 167 ℃, is the lightest plastic containers. NOTE: If the temperature is too high, the body will not have gas diffusion out. In addition, some microwave meal box body is made of PP, but the lid is made of the 6th PS, carefully checked before use, if such a situation should first remove the lid after heating. Products compared to PE, PP products slightly better heat resistance, typical Lock & Lock glass using temperature can reach 110 ℃, but then there is a high temperature melting softening and dangerous, and should be avoided.
6, polystyrene (PS) used in: ice cream containers, snack, cheap transparent products, foam, CD boxes, cups, snack, insulation material layer. Advantages: transparency, heat resistance is superb, used to install high-temperature foods, such as bowl of instant noodles (now multi-use paper containers), cold resistance, a variety of ice also love to use this container.