While plastics bring convenience to people, they also pose a threat to the environment. At present, plastic pollution has replaced climate change as the biggest issue in the global environmental field. In this context, various countries have introduced plastic recycling and recycling policies, and it has become a global consensus to establish a plastic recycling system and realize a closed-circuit plastic circulation. With these policies put forward, plastic recycling economy has also entered the public vision
China is the world’s largest plastic production and consumption, plastic consumption accounted for 15% of the global proportion. At the same time of large-scale production and use of plastic products, it is inevitable to produce a lot of waste plastic. Faced with the huge pressure of plastic pollution, the Chinese government has taken a number of policies and actions successively: In 2008, the Plastic Banning Order was issued; in 2012, the Soil Pollution Prevention and Control Action Plan was issued; in 2017, the import of waste plastics was gradually banned; in 2018, the construction of waste-free cities was promoted; in 2019, the sorting of household waste was carried out; and in 2020, the Opinions on Further Strengthening the Control of Plastic Pollution was issued.
The successive introduction of these policies has effectively created a trinity of “government supervision, industry self-discipline and social participation” collaborative control system for plastic pollution, and achieved great achievements. On the one hand, the policy promotes the change of social concept. Low-value waste plastics can also become resources. On the other hand, it encourages related enterprises to transform to circular economy and promotes the industry to step into the track of standardized, orderly and sustainable development.
However, on the whole, the recycling of plastic waste in China is still characterized by high waste rate, low recovery rate and low recovery rate. According to the statistics of the Recycled Plastics Branch of China Material Recycling Association, China will recycle 18.9 million tons of domestic plastic waste in 2020. Due to the high output in 2020, the proportion of waste plastic recycling dropped to only 23.09 percent. China’s plastic recycling road is still a long way to go.
Increasing attention to the plastics issue is creating huge challenges and opportunities for the chemical industry, which is further up the value chain. How to reduce our dependence on oil from the perspective of raw materials; How chemicals and additives used in the production of plastics affect the potential for reuse of finished products; Some plastic packaging is made from a variety of materials and is extremely difficult to recycle… These issues are driving the demand for more innovative and easily recyclable materials and related solutions in the plastics value chain. By creating a new material recycling process, the chemical industry will push the plastics economy into a recycling mode.
Recycling is the first step in plastic recycling. At present, the main recycling methods of waste plastics are mechanical recycling and chemical recycling. Both have their advantages and disadvantages and complement each other.
Mechanical recycling refers to the separation and cleaning of synthetic materials so that they can be directly reused as polymers. It is the main method of plastic waste recycling. However, mechanical recycling itself has great limitations: difficult sorting, high cost, low income, can only be used to deal with high value, single category, relatively clean plastics. But in reality, most of the plastic waste is mixed with other household waste, showing the characteristics of “dirty and messy”, recycling is very difficult.
The introduction of garbage sorting policy has largely relieved the pressure of sorting, so that low-value waste plastics can be sorted out from garbage with low cost and high efficiency. But much of the post-sorting work is still heavily dependent on technology. Many products are made of multiple materials to meet functional requirements, making recycling and separation difficult. The complexity of products such as food preservation packaging, synthetic fabrics for clothing, and a wide variety of plastic bottles makes recycling extremely difficult.
At present, many chemical enterprises have developed processing AIDS to improve the efficiency of mechanical recovery. For example, custom surfactants developed by Evonik, a speciality chemicals company, can be used in deinking and de-labelling processes to quickly remove ink and labels from plastic packaging. Defoaming agent can prevent excessive foam generation, thus simplifying the washing process; Wetting agent can increase the mobility of the lye to remove the label adhesive; The dehydrating agent AIDS the subsequent drying process, saving energy and time.
On the other hand, in order to improve the performance of recycled plastic products, so that the recycled plastic has the same quality as the original plastic, additives and processing AIDS can also play a role. Take the example of Evonik additive Vestoplast ®, which is key to the recycling of multi-layer packaging films. Vestoplast ® is a chemical cousin of PE and PP(two common plastic film materials), which makes the two materials compatible with each other and improves the impact strength or fluidity of recycled feedstock, facilitating the reuse of materials such as for injection molding.
Chemical recycling is an effective complement to mechanical recycling. Compared with mechanical methods, chemical recycling breaks down the polymer chains of recycled waste plastics into monomers. As a result, even very dirty, stained waste containing additives or foreign materials can be recycled as valuable raw materials and turned into new plastics, thus closing the material cycle.
However, there are still many challenges in the practical development of chemical recycling of waste plastics, and there is plenty of room for discussion both in terms of technical paths and commercial potential. “Chemical recycling is the best way of recycling, through high temperature catalysis, cracking plastic into monomers and then as a raw material to produce products, to ensure its full use.” Pang Guanglian, deputy secretary-general of the China Petroleum and Chemical Industry Federation, said, “Chemical recycling and chemical recovery are definitely a development direction in the future, but the current technology is not mature, we still need to discuss its economic issues, and the cost and investment are relatively high.”
The development of plastic recycling economy is a complex global issue. From a technical perspective, we need a comprehensive assessment system to improve sustainability across the entire plastic life cycle, from access to raw materials and manufacturing to better recycling, disposal and reuse options, and a full understanding of the environmental impact of each process. From the business level, it requires the industry chain to establish a wide range of cooperation throughout the whole value chain, the whole life cycle of the closed-loop system. It also relies on government policy guidance and improved consumer awareness.
At present, the global consensus of “treating plastic pollution and developing circular economy” has been established, and the industrial chain is gradually establishing more extensive cooperation. For example, a number of global chemical, packaging, and brand giants have made voluntary commitments to “plastic reduction” or “plastic recycling” to promote the “plastic recycling economy” shift from policy orientation to market behavior. In addition, government agencies, NGOs, industry associations and others have launched several initiatives to promote plastic recycling. And the cases of cooperation between enterprises are numerous
It should be said that the global cooperation consensus is the basic platform for the development of plastic recycling economy, in order to promote the innovation of related recycling technology. Only with the rapid development of technology, can we truly solve all kinds of difficult problems in sorting, recycling, recycling and other links of plastic recycling economy, so as to give full play to the economic, environmental and social benefits of plastic recycling.
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