Among the three, HDPE has better thermal, electrical and mechanical properties, while LDPE and LLDPE have better flexibility, impact properties and film-forming properties. LDPE and LLDPE are mainly used in packaging film, agricultural film and plastic modification. And HDPE is widely used in injection films, pipes, daily necessities and other fields.
2. Polypropylene: Relatively speaking, polypropylene has more varieties, more complex uses and more fields. The main varieties are homopolypropylene, block polypropylene (copp) and random polypropylene (rapp).
According to different uses, homopolymerization is mainly used in drawing, fiber, injection molding, BOPP film and other fields. Polypropylene is mainly used for injection-molded parts of household appliances, modified raw materials, daily injection-molded products, pipes and so on. Random polypropylene is mainly used in transparent products, high-performance pipes and so on.
3.PVC: Because of its low cost and self-flame retardant characteristics, it is widely used in the construction field, especially in sewer pipes, plastic steel doors and windows, plates, artificial leather and so on.
4. Polystyrene: As a transparent raw material, it is widely used, such as car lampshades, daily transparent parts, transparent cups and cans.
5.ABS is a widely used engineering plastic with excellent physical, mechanical and thermal properties. Widely used in household appliances, panels, masks, components, accessories and so on. Especially household appliances such as washing machines and electric fans. In addition, it is also widely used in plastic modification.
Extended data
According to different plastic molding methods, it can be divided into film pressing, lamination, injection, extrusion, blow molding, plastic casting and reaction injection.
Film-pressed plastics are mostly plastics with physical properties and processability similar to those of general solid plastics; Laminated plastics refers to the fiber fabric impregnated with resin, which is combined into a whole through superposition and hot pressing; Injection molding, extrusion and blow molding are mostly plastics with similar physical properties and processability to ordinary thermoplastics.
Casting refers to the liquid resin mixture that can be hardened into a certain shape product by pouring it into the mold without pressure or with a little pressure, such as MC nylon; Reaction injection plastic is a kind of plastic, such as polyurethane, which is solidified into a certain shape by liquid raw materials.
There are two types of common thermoplastics: crystalline and amorphous:
1. Crystalline plastics are translucent, opaque or opaque in appearance, transparent only in the film state, and the hardness varies from soft to horny.
2. Amorphous rubber is generally colorless, completely transparent without additives, and its hardness ranges from hard to horny rubber (additives such as plasticizer are often added at this time). Thermosetting plastics usually contain fillers and are opaque, such as transparent without fillers. Elastomer has the feeling of rubber and a certain stretching rate.
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