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

The proportion of PLA and PBAT degradable plastics industrial structure is among the best

With the development of economy, consumption upgrading and the rapid development of express industry and takeout industry, plastic has become a necessity in our daily life, such as express packaging, takeout packing box, supermarket shopping bag and so on. In recent years, with the increasing consumption of plastics, the problem of environmental pollution has become increasingly apparent, which has brought great harm to human health and ecological environment. "A major problem is the fate of plastic decomposition products, such as micro plastics and chemical additives, many of which are known to be toxic and harmful to human and wildlife health and ecosystems," said Inge Anderson, executive director of the United Nations Environment Programme The human body is vulnerable to plastic contamination of water sources in many ways, which can lead to hormonal changes, developmental disorders, reproductive abnormalities and cancer. Plastic will be ingested by people through seafood, beverages and even salt; When plastics are suspended in the air, they are inhaled and penetrate the skin.

The treatment of plastic pollution should mainly start from four aspects: source reduction, recycling, substitution and cleaning. Replacing traditional plastics with degradable plastics in the natural environment is an important part of the above treatment work. Through a series of reactions, biodegradable plastics are finally converted into compost under photosynthesis to realize degradation.

Degradable plastics refer to a kind of plastics whose properties can meet the use requirements, whose properties remain unchanged during the storage period, and which can degrade into environmentally friendly substances under natural environmental 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 industrial structure, the proportion of traditional starch based and PLA degradable plastics ranks first, accounting for 32%; PBAT accounts for 23%, and the three occupy most of the market of fully biodegradable plastics. PBS accounts for 8% of the market share, but due to its weak overall commercial attraction, there are fewer manufacturers developing PBS than PLA and PBAT.

PLA and PBAT are the most promising degradable plastics.

The full cost of PLA is higher than that of PBAT

From the perspective of cost, the cost of PLA is slightly higher than that of PBAT in recent 5 years. PLA monomer raw material lactic acid is mainly fermented by corn and other food crops. In recent years, the domestic price of lactic acid is relatively stable, and the production cost of lactic acid is high. The complete cost of PLA products on a typical industrial scale is about 16000 yuan / ton. PBAT monomer comes from the petrochemical route, and the product price is affected by the price of crude oil. Due to the relatively low price of raw materials, the complete cost of PBAT is lower than that of mainstream degradable plastics, about 13000 yuan / ton, so PBAT has more competitive advantages.

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

There are two production technologies of polylactic acid, namely "one-step" and "two-step"; The technology of Shanghai tongjieliang company comes from Tongji University and adopts one-step production process. Now it has the production capacity of "lactic acid polylactic acid". It is also the only enterprise in China that adopts "one-step" at present. The "two-step" production process of polylactic acid has a high technical barrier - lactide technology. At present, this technology is mainly mastered by overseas companies NatureWorks and corbion PURAC. At present, China is still in the initial stage, and the domestic polylactic acid technology mainly depends on the cooperative research and development of enterprises and scientific research institutions. COFCO technology, the most leading technology, has mastered the lactide production process and processing technology in cooperation with grat, Belgium, and the lactide production project is only being promoted. Generally speaking, domestic enterprises are currently subject to the technical level.

At present, the mainstream production method of PBAT is co esterification method, which has the advantages of simple operation, short process flow, high raw material utilization, short reaction time and high production efficiency. Due to the low technical barriers to the production of PBAT and the maturity of China's technical development, China's PBAT production capacity occupies a leading position in the world, with more capacity under construction.

The downstream applications of PLA and PBAT overlap, and blending can improve the properties of products

PBAT not only has good ductility, breaking elongation, heat resistance and impact resistance, but also has excellent biodegradability. It is the main body of membrane material; It is widely used in plastic packaging film, agricultural film 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 plastic, while PBAT belongs to soft plastic, which can be roughly regarded as polypropylene and polyethylene in petrochemical products. Moreover, PLA with poor film blowing processability is mostly blended with PBAT with good toughness, which can improve the film blowing processability without damaging its biodegradability.

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