This article takes you to understand the similarities and differences in the development of degradable plastics PAL and PBAT industries

PLA and PBAT are among the best in the industry structure of degradable plastics

With the development of the economy, consumption upgrades and the rapid development of express delivery and takeaway industries, plastics have become a necessity in our daily life, such as express packaging, takeaway packaging boxes, supermarket shopping bags, etc. In recent years, the consumption of plastic has continued to increase, and the environmental pollution problem has become increasingly apparent, which has brought great harm to human health and the ecological environment. UNEP Executive Director Inge Anderson said: "A major issue is the fate of plastic decomposers, such as microplastics and chemical additives, many of which are known to be toxic and hazardous to human and wildlife health and ecosystems. "The human body is vulnerable in multiple ways to plastic pollution in water sources, which can lead to hormonal changes, developmental disorders, reproductive abnormalities and cancer. Plastics are ingested by people through seafood, beverages, and even table salt; when plastics are suspended in the air, they are inhaled and penetrate the skin.

The control of plastic pollution should mainly start from four aspects: reduction, recycling, replacement and cleaning at the source. Among them, replacing traditional plastics with degradable plastics in the natural environment is an important part of the above-mentioned governance work. Biodegradable plastics are finally converted into compost under photosynthesis through a series of reactions to achieve degradation.

Degradable plastics refer to a class of plastics whose various properties can meet the requirements of use, remain unchanged during the storage period, and can be degraded into environmentally harmless substances under natural conditions after use. According to the classification of raw materials, it can be divided into bio-based degradable plastics and petroleum-based degradable materials. The representative of bio-based degradable plastics is PLA, and the representative of petroleum-based degradable materials is PBAT.

At present, in the global biodegradable plastics industry structure, traditional starch-based and PLA degradable plastics account for the first place, accounting for 32%; PBAT accounts for 23%, and the three occupy most of the market for fully biodegradable plastics. PBS has an 8% market share, but due to its weak overall commercial appeal, there are currently fewer manufacturers developing PBS than PLA and PBAT.

PLA and PBAT are the most promising biodegradable plastics.

PLA full cost is higher than PBAT

From a cost perspective, the cost of PLA is slightly higher than that of PBAT in the past five years. PLA monomer raw material lactic acid is mainly produced by fermentation of grain crops such as corn. In recent years, the domestic lactic acid price has been relatively stable, and the production cost of lactic acid is relatively high. The complete cost of a typical industrial-scale PLA product is about 16,000 yuan/ton. PBAT monomers come from petrochemical routes, and product prices are affected by crude oil prices. Due to the relatively low price of raw materials, the complete cost of PBAT is the lowest among mainstream degradable plastics, about 13,000 yuan/ton, so PBAT has a more competitive advantage.

PLA is still conquering lactide technology, while PBAT production technology is mature

There are two production technologies for polylactic acid, namely "one-step method" and "two-step method"; Shanghai Tongjieliang Company's technology comes from Tongji University, using one-step production process, and now has the production capacity of "lactic acid-polylactic acid" It is also the only company in China that adopts the "one-step method". The "two-step" generation process of polylactic acid has a high technical barrier - the lactide technology process. At present, this technology is mainly mastered by overseas companies NatureWorks and Corbion-Purac. my country is still in the initial stage, and domestic polylactic acid technology mainly relies on the cooperative research and development of enterprises and scientific research institutions. The most advanced COFCO Technology has cooperated with Belgian Glatter, and has mastered the production technology and processing technology of lactide, and the lactide production project is also Only in progress. In general, domestic companies are currently constrained by the level of technology.

At present, the mainstream production method of PBAT is the co-esterification method, which is simple in operation, short in process flow, high in raw material utilization, short in reaction time and high in production efficiency. Due to the low production technical barriers of PBAT and the mature technology development in my country, my country's PBAT production capacity occupies a leading position in the world, and there are more production capacity under construction.

PBAT not only has good ductility, elongation at break, heat resistance and impact resistance, but also has excellent biodegradability. It is the main body of film materials; it is widely used in plastic packaging films, agricultural mulching films and other film materials. The downstream applications of PLA mainly include: biomedicine, coatings, industrial materials and packaging.

Although the application fields of PLA and PBAT overlap, they have different characteristics. For example, PLA belongs to hard plastics, while PBAT belongs to soft plastics, which can be approximated as polypropylene and polyethylene in petrochemical products. Moreover, PLA with poor blown film processability is often blended with PBAT with good toughness, which can improve the blown film processability without compromising its biodegradability.

On the whole, PLA and PBAT have a relatively high degree of industrialization, which is also the direction of my country's current vigorous development. Compared with PBAT, the cost of PLA is higher, and it is more difficult to break through technical barriers, and China's development is still in a relatively preliminary stage. However, due to the overlapping fields of PLA and PBAT in the downstream application field, they can make use of the performance advantages of both sides, as well as price, cost and technical advantages, to make mixed products to achieve the highest cost performance.