0 1-PET (polyethylene terephthalate) Common uses of polyethylene terephthalate: mineral water bottles, carbonated beverage bottles, etc.
Polyethylene terephthalate is a common resin in life, which has good mechanical properties, impact strength 3~5 times that of other films, good folding resistance, high transparency, blocking ultraviolet rays and good gloss. Transparent plastic bottles made of it are often called "Potter bottles". This kind of plastic usually has a maximum heat-resistant temperature of 65℃ and a minimum cold-resistant temperature of -20℃, so it is generally only suitable for normal temperature liquids or low temperature liquids. If it is filled with high-temperature liquid or directly heated, it is easy to be thermally deformed and produce substances harmful to human body. Moreover, scientists have found that this plastic product may release carcinogens after being used for more than 10 months, which is toxic to human body. So this kind of plastic bottle should be sorted and discarded immediately after use. Don't use it as a drinking cup, and try not to use it as a storage container to hold other items, so as not to cause health problems, which is not worth the candle.
02—HDPE (high density polyethylene) Common uses of high density polyethylene: cleaning products, bath products, white medicine bottles, plastic containers for skin care products, and plastic bags used in supermarkets at present.
High density polyethylene (HDPE) is a nonpolar thermoplastic resin with high crystallinity. Its melting temperature is between 120~ 160℃, and the general use temperature should be controlled within 100℃. In the next industrial products, the highest temperature it can withstand is 1 10℃. If plastic bags for food are marked, they can be used. Plastic containers containing cleaning products and bath products can be reused after small-scale self-cleaning, but these containers are usually not easy to clean, and the original cleaning products remain, which becomes a hotbed of bacteria and cannot be cleaned thoroughly. Therefore, in daily life, it is best not to recycle high-density polyethylene products, but to replace them on time and in time. Waste products should be recycled and classified to prevent environmental pollution and secondary pollution.
03—PVC (polyvinyl chloride) Common uses of polyvinyl chloride: raincoats, plastic films and building materials. PVC is a white powder with amorphous structure, and its branching degree is small, and its relative density is about 1.4. It begins to decompose at the glass transition temperature of 77~90℃ and around 170℃, and has poor stability to light and heat. Exposure to sunlight above 100℃ or for a long time will decompose to produce hydrogen chloride, which will further decompose automatically and cause discoloration.
This plastic has good plasticity and low price, but plastic products made of this material are prone to produce two kinds of toxic and harmful substances: one is monomolecular vinyl chloride which is not fully polymerized in the production process, and the other is harmful substances in plasticizer. These two substances are easy to precipitate when they encounter high temperature and oil, and toxic substances are easy to cause cancer after entering the human body with food. So, don't let it be heated when using it.
04—LDPE (Low Density Polyethylene) Commonly used low density polyethylene: cling film, plastic film, etc. Low density polyethylene (LDPE), also known as high pressure polyethylene, is a plastic material. Taking ethylene as raw material, it is sent into a reactor and polymerized by high pressure compression under the action of initiator. The materials coming out of the reactor are separated by a separator, and then melted, extruded, granulated, dried and mixed. It is suitable for various molding processes of thermoplastic molding and has good molding processability. Low density polyethylene (LDPE) is mainly used as film products, as well as injection-molded products, medical devices, pharmaceutical and food packaging materials, blow-molded hollow products and so on. The heat resistance of plastic wrap is not strong. Qualified PE plastic wrap will melt when the temperature exceeds 1 10℃, leaving some plastic preparations that cannot be decomposed by human body. If food is wrapped in plastic wrap and heated directly, the oil in food will easily dissolve the harmful substances in plastic wrap at high temperature, which is harmful to human health. Therefore, it is best to take away the wrapped plastic wrap before putting the food in the microwave oven.
05—PP (polypropylene) Common uses of polypropylene: packaging bags, special lunch boxes for microwave ovens, etc. Polypropylene is a semi-crystalline thermoplastic. High impact resistance, strong mechanical properties, resistance to various organic solvents and acid and alkali corrosion. It is widely used in industry and is one of the common polymer materials. Australian coins are also made of polypropylene.
The microwave lunch box is made of this material, which is resistant to high temperature 130℃ and has poor transparency. It is the only plastic box that can be directly heated in the microwave oven and reused after cleaning. It should be noted that some microwave lunch boxes are made of 05 PP, but the lid is 06 PS polystyrene. PS has good transparency, but it is not resistant to high temperature, so it can't be put in the microwave oven with the box. The appearance of PS polystyrene 06 is easy to distinguish from PP, so, to be on the safe side, take off the lid of the container before putting it in the microwave oven.
06-PS (polystyrene) Common uses of polystyrene: instant noodle boxes in bowls, fast food boxes, etc. Polystyrene is the product of addition polymerization of styrene monomer, which was originally obtained from the volatile oil in natural resin balsam. Polystyrene has good corrosion resistance to acid, alkali, salt, mineral oil, organic acid and lower alcohol, but it will soften or dissolve in organic solvents such as acetone, esters and aromatic hydrocarbons. Good insulation, good transparency, high refractive index, good water resistance and good coloring, and can be made into various colored plastic products. Very good fluidity when melting, easy to process, and can be molded and extruded.
Polystyrene can be used as a material for making bowl-filled instant noodle boxes and foamed fast food boxes. Heat-resistant and cold-resistant, but it can't be put into the microwave oven to avoid releasing chemicals when the temperature is too high. Moreover, it can't be used to hold strong acids and alkaline substances such as orange juice, because it will decompose polystyrene that is not good for human body.
07—Common use of PC and other PCs: kettle, space cup, milk bottle, etc.
It is a widely used material, especially for making milk bottles, space cups and so on. Because it contains bisphenol -8, it is controversial. Experts pointed out that in theory, as long as bisphenol is completely converted into plastic structure in the production process, it means that there is no bisphenol in the product at all, let alone released. However, if a small amount of bisphenol does not freeze the special plastic structure, it may be released into food or drink. Therefore, when using this plastic container, the food should be stored and disinfected in strict accordance with the requirements of the instructions to avoid reusing the aged or damaged products. The higher the temperature, the more bisphenol is released and the faster it is. So don't put hot water in a water bottle. If your kettle number is, the following methods can reduce the risk. Don't heat it when using it, and don't direct it in the sun. No dishwasher or bowl dryer is needed to clean the kettle. Before the first pass, it was washed with baking soda and warm water and dried at room temperature, in vain. If the container is dropped or damaged, it is recommended to stop using it, because if there are tiny pits on the surface of plastic products, it is easy to hide bacteria. Avoid reusing aging plastic appliances.