塑料主要是指以合成树脂为基础,并可以塑制成型的材料。工程塑料是指能承受一定的外力、具有良好的尺寸稳定性、在一定的温度仍能保持优良性能的塑料。与金属相比,它们的比重较小(仅为钢的八分之一左右);化学稳定性好,有的塑料与王水也不起化学反应;有良好的耐磨性和绝缘性等等。因此,随 Plastic mainly refers to the synthetic resin-based, and plastic molding materials. Engineering plastics are those that can withstand a certain amount of external force, have good dimensional stability, and maintain good performance at a certain temperature. Compared with the metal, their proportion is small (only about one eighth of the steel); chemical stability, and some plastic and aqua regia can not afford chemical reactions; have good wear resistance and insulation, etc. . So, with