LDPE (low density polyethylene) code 4, also known as high pressure polyethylene, the raw material is milky white, odorless and non-toxic, with good transparency, good flexibility, alkali resistance, but poor heat resistance, etc. The density is all polyethylene. The lowest in ethylene, it will melt and release toxic substances when it exceeds 110 ℃, mainly used for cling film, plastic film, etc.
PP (polypropylene) code 5, also known as Baizhe glue, has low density, transparent and light appearance of raw materials, non-toxic and tasteless, high strength and elasticity, chemical resistance, collision resistance, high temperature resistance of 100~120 degrees Celsius, can be put It is heated in a microwave oven, but it is forbidden to use recycled products to hold food. It is often used in plastic lunch boxes, water cups, food packaging boxes and other products. PP materials are used. Because of these characteristics of PP, Australia's currency is made of this plastic. .
PS (polystyrene) code 6, also known as hard glue, the hardness will be higher than PP, the raw material has high light transmittance, colorless and odorless, easy to dye, but poor toughness, easy to brittle, the temperature exceeds 70 ℃ will release harmful Substances are commonly used in disposable foam lunch boxes, packaging linings, decoration materials, etc. Because it is not easy to recycle, they are gradually replaced by paper materials.
PA (polyamide) is also called nylon. It has no code. The raw material is non-toxic and odorless, with good toughness, wear resistance, heat resistance and chemical resistance. There are many kinds of PA plastics. Especially now, by mixing various fiber materials, PA Various properties of plastics have been significantly improved, and they have replaced some metals, and are widely used in auto parts, household appliance housings, protective equipment and other fields.
ABS plastic has no code. It is a composite of three substances: acrylonitrile (A), butadiene (B) and styrene (C). It is also called ABS resin, so ABS also has the common properties of these three substances. Impact resistance, heat resistance, low temperature resistance, good comprehensive performance, cheap price, wide range of uses, ABS plastic is non-toxic, tasteless, and the appearance is translucent or transparent particles, many parts in automobiles are made of ABS plastic, in household appliances , The parts on the office machine are also made of ABS.
Other types, code 7, include acrylic, polycarbonate, polylactic acid, etc. The characteristics of these plastics are that they cannot be heated in a microwave oven, cannot be sterilized at high temperature, and cannot be exposed to direct sunlight, because this may release bisphenol A, which will cause harm to the human body.
