1. Thermosetting plastic, which is characterized by curing at a certain temperature after a certain time of heating or adding curing agent. The cured plastic is hard and insoluble in any solvent, and cannot be softened again by heating. If the heating temperature is too high, it will decompose. The common thermosetting plastics include bakelite, electric jade, decorative board and unsaturated polyester plastic.
2. Thermoplastic, which is characterized by softening by heating and hardening by cooling. Generally, only physical changes keep its chemical nature during processing. The resin of this kind of plastics is mostly made by addition polymerization. Common thermoplastics include: nitrate fiber plastic, acetate fiber plastic, polyethylene plastic, polypropylene plastic, polystyrene plastic, polyvinyl chloride plastic, etc. For example, our common mineral water bottles and plastic bags.
General purpose plastic, which mainly refers to a kind of plastic with large output, wide use and low price. They account for about 80% of the total output of plastics. The main varieties are: polyethylene, polyvinyl chloride, polypropylene, polystyrene, phenolic and amino plastics.