The use of natural resin can be traced back to ancient times, but the modern plastic industry was formed in 1930, and has made rapid development in the past 40 years. The name resin comes from the lipid secreted by trees. The earliest natural resins used by human beings are rosin, shellac and so on. The output of natural resin is limited by the region, but the output is not large, the quality is not high and the use is limited. In order to find a substitute for natural resin, 1846 people made nitrocellulose from cellulose (cotton) and nitric acid, and mixed wet nitrocellulose with camphor to make a substitute for shellac. 1872 was completed. Although it has been 100 years since its discovery, it is still widely used, commonly known as celluloid, such as table tennis, toys, combs, buttons and so on. With the growth of human demand for plastic materials and the improvement of scientific and technological level, people have developed synthetic resins which are much more widely used than natural resins. Synthetic resin is a high molecular weight resinous substance made of low molecular weight compounds through chemical reaction. It is generally solid at room temperature and pressure, and some are viscous liquids. The first synthetic resin is thermosetting phenolic resin (bakelite), which is made of phenol and formaldehyde under the action of catalyst. Since the establishment of the first phenolic resin factory in 1907, it has entered the period of polymer synthesis. 193 1 year, the first industrial production of thermoplastic resin PVC resin began. Since then, the synthetic polymer industry has developed rapidly, and polystyrene, polyvinyl acetate and polymethylmethacrylate have been industrialized one after another. At present, there are about 30 kinds of resins produced in industry. Among the three synthetic materials (synthetic resin and plastic, synthetic rubber and synthetic fiber), synthetic resin is the earliest, the largest output and the most widely used. According to statistics, the world output of synthetic resin in 1995 was about1.200 million tons, and that in Chinese mainland was about 4.4 million tons.