The plastic is widely used in industry, because of its features, and it has replaced the metal, wood and paper, so it is playing an increasing role in the economy. We can know that from its amount and wide application. According to the data, the ferrous metals take up 60% in the total consumption of structural materials in 1960s, however, in 1990s, the synthetic plastics takes up 78%, and the ferrous metals only take up 19%. There is no doubt that the plastic has the widest usage.
But due to some of its features, it is nondegradable after the usage, so after those years, the plastic also caused a lot of problem. In 1997, the total output of the plastic all around the world reached 140 million tons, which equals to the volume of 1 billion ton steel. In addition, with the development of economy and society, the amount of the plastic keeps increasing, which also means that the conflict between the plastic and environment will be severer. Thus we must take actions, and find the good waste plastic recycling machine.