October 15, 2024 – Polypropylene Ash Content: A Key Factor in Determining Material Quality and Application
Polypropylene, a widely used plastic material, leaves behind a non-volatile residue known as polypropylene ash after high-temperature incineration. This ash content, typically controlled to an extremely low level of 0.005% or less in high-quality polypropylene products, is referred to as low-ash polypropylene in the industry. Elevated ash levels can adversely affect the performance and application scope of polypropylene products. The sources of ash are diverse, including catalyst residues, raw material impurities, non-combustible substances in additives, and impurities introduced during packaging and transportation.
Low-ash polypropylene, characterized by its unique low ash and low metal element residue properties, has demonstrated extensive prospects in multiple high-end applications. It has become an indispensable material in the field of dielectric materials, particularly for battery separator materials and capacitor separator materials. Additionally, low-ash polypropylene finds application in ultra-transparent materials, infant products, and household appliances. According to statistics, the consumption in the low-dielectric material sector accounts for a staggering 93%, with battery separator materials and capacitor film materials being the primary consumption directions.
The production of low-ash polypropylene is challenging, and the global supply is highly concentrated. Currently, Borealis, Daihan Oil Chemical, and TPC Singapore are the three major suppliers of low-ash polypropylene, accounting for approximately 92% of the global total supply. In China, the supply of low-ash polypropylene for capacitor films is almost entirely dependent on these three companies, with a market share of 98%. These companies offer a diverse range of low-ash polypropylene resin grades, such as Daihan Oil Chemical’s S801 and 5014L HPT, Borealis’ HC300BF and HC312BF, and TPC Singapore’s FS3028 and FS3029, all of which occupy a significant position in the market due to their excellent performance.
In the face of the dominant position of foreign companies in the field of low-ash polypropylene, China is actively seeking breakthroughs. Currently, only a few domestic enterprises, such as Zhongyuan Petrochemical, have the capability for large-scale production of ultra-low-ash polypropylene, and the market supply still relies heavily on imports. However, it is worth mentioning that domestic enterprises like Zhongyuan Petrochemical have made significant progress in the field of low-ash polypropylene through the adoption of innovative processes such as direct polymerization. Their products, such as PPHFC03, have achieved high levels in terms of melt flow rate, dielectric constant, melting point, and stereoregularity. Although the ash content is slightly higher than that of special polypropylene for electrical films produced through process devolatilization, its excellent heat resistance makes it comparable to imported products in applications such as capacitor films and lithium-ion battery separators.
Overall, low-ash polypropylene, as a high-performance material, has demonstrated wide application prospects in various fields. Although the global supply is currently highly concentrated, with active research and production efforts in countries like China, broader domestication and application of low-ash polypropylene are expected in the future.