The crux of the difficulty of plastic film recovery lies in "film".

After more than 30 years of development and application, plastic film mulching has become one of the most important agronomic technologies in China, and even formed a situation that agricultural production can not be carried out without plastic film mulching in Northwest China. At present, on the one hand, plastic film mulching has been incorporated into the major popularization and application technology of national and local agricultural production, on the other hand, plastic film residual pollution is also the key content of national "one control, two reduction, three basic" agricultural non-point source pollution prevention and control. Therefore, it is an extremely arduous task to achieve a substantial increase in the recovery rate of plastic film on the basis of the continued expansion of plastic film coverage. the prevention and control strategy of source control and efficient recovery of two legs must be adopted to ensure that, as recently put forward by the Ministry of Agriculture, the recovery rate of agricultural film in the current season will reach more than 80% by 2020.

Plastic film recovery is a very difficult task, which includes two processes: plastic film recovery and recycling. In view of the actual agricultural production and the characteristics of residual plastic film, the residual film recovery machines developed in China, such as spring tooth type, drum type, pneumatic type, roller winding type and tooth chain type, have reached the advanced level in the world, but there is still a gap with the actual agricultural production in our country. At present, the biggest challenge is to improve and simplify the machine structure, reduce the operating cost and improve the work efficiency, and it is also the key to receive the field head from the field.

The recycled waste plastic film is mainly treated in the following ways. One is the landfill method, but because the residual film is not perishable, it will eventually cause pollution to the environment, so this method is used less and less. The other is the incineration method, which uses the heat generated by the combustion of plastic film for power generation or other aspects. The third is recycling, by decomposing the waste plastic film, recovering ethylene or refining petroleum products for reuse, or recycling them to make plastic products.

More and more countries have tended to achieve the recycling and utilization of waste film through a variety of technical means. According to the different mechanism, the recycling of waste plastic film can be divided into physical recycling, chemical recycling and energy recycling. The calorific value of waste agricultural film is very high, so there is great potential for thermal energy recovery. Japan and Germany have established special waste plastic treatment plants, showing good economic benefits.

Degradable plastic film instead of PE plastic film is the best way to solve the problem of farmland residual film pollution, which can solve the problem of plastic film residue from the source. According to the degradation mechanism, it can be divided into two kinds of products: photooxidative degradation and total biodegradation. In China, after recent years of research, the system integration technology system of polyester material engineering equipment has been formed, a large-scale degradable material synthesis workshop has been established, and shows a good application prospect. It is also a research hotspot to use promoters to degrade ordinary PE plastics. The degradable PE materials can be produced by adding the promoters which can catalyze the photothermal degradation of polyethylene into PE in a special way. In recent years, great progress has been made in the research and application in this area in China, but it is necessary to strengthen the related research and make a breakthrough in terms of mechanism and controllability of degradation, so as to ensure the safe application of this kind of plastic film products.

Generally speaking, due to the complexity of degradation and application of degradable plastic film, the degradable plastic film of the same formula has different degradation performance to different crops in different places, so it can be widely used only through application research. Compared with ordinary polyethylene mulch film, the high cost of degradable film is a fatal problem. With the development of material science and the improvement of technology in the future, the biodegradable mulch film with biomass as the main raw material will replace the traditional polyethylene mulch film and become the ultimate way to solve the "white pollution".