1 Type of plastic
(1) According to the characteristics of use, plastics are classified into general plastics, engineering plastics and special plastics. General-purpose plastics refer to plastics with large output, wide application, good shape and low price, such as polyethylene, polypropylene, phenolic and so on. Engineering plastics can bear a certain external force, have good mechanical properties and high and low temperature resistance, and have good dimensional stability. It can be used as engineering plastics, such as polyamide and polysulfone. Special plastics have special functions such as fluoroplastics and silicones.
(B) According to physical and chemical properties, it can be divided into thermosetting plastics and thermoplastics. Thermosetting plastics are plastics that cure or have insoluble (melting) properties under heat or other conditions. The advantages of thermosetting plastics are that the strength and heat resistance are good, and the pressure is not easily deformed; the disadvantage is that the molding process is complicated and the production efficiency is low. Thermoplastic refers to a plastic that can be repeatedly softened and cooled and hardened in a specific temperature range. The utility model has the advantages of simple molding process, high productivity, certain mechanical properties, and reusable recycling; the disadvantage is poor heat resistance and low rigidity.
2 plastic ingredients
The plastic is mainly composed of synthetic resin, and an appropriate amount of additives are added to increase the process performance and performance. Additives include: fillers and reinforcing materials, fillers, plasticizers, curing agents, stabilizers, lubricants, antistatic agents, flame retardants, and the like.
3 modified plastic
The characteristics of plastics are characterized by light weight, no rust, good impact resistance, high transparency, good wear resistance and insulation, low thermal conductivity, good formability and colorability, low processing cost, etc. The use of a large number of plastics can comprehensively reflect the requirements for the design performance of the car, namely, lightweight, safe, anti-corrosion, beautiful appearance and comfort, etc., and is conducive to reducing costs and saving material resources. However, due to the poor dimensional stability of ordinary plastics, large thermal expansion rate, easy burning, and aging, many characteristics cannot be compared with metal materials. Therefore, the plastic used in automobiles is not a single type, but is modified, also known as "modified plastic."
