PVDF: Product Upgrades by Technical Innovation

By Jiang Yanyan, CNCIC Consulting Department

PVDF (polyvinylidene fluoride) is produced through the polymerization of vinylidene fluoride monomer. In addition to excellent resistance to chemical corrosion, high temperature, oxidation, weather and radiation, it has uncommon features such as piezoelectric properties, dielectric properties and thermoelectric properties. Products are mainly classified into powdery varieties (used in lithium cell binders and coatings) and granular varieties (used in lithium cell diaphragms, water treatment membranes and product processing).

Rapid growth, insufficient range of high-end products

China’s PVDF sector is growing rapidly today. The capacity was 11 kt/a in 2010 and reached 51 kt/a (including the capacity of foreign-owned companies) in 2015. The average annual growth of capacity was 35.9% during the period. It is expected that by the end of 2016, total capacity will increase to 80 kt/a. Restricted by the sector’s level of technical development, however, it has surplus capacity for mid-market/low-end products and insufficient capacity for high-end products. Output was around 25 kt in 2015, with an average operating rate of only 50%.
Low-end (coating-grade) products are predominant in small enterprises, whereas the needs of high-end applications such as the manufacture of membranes cannot yet be satisfied.
Prices of general-purpose PVDF products in China in 2013 were around 35% lower than in the previous year. New units also started production during 2014-2016. Prices have declined steadily overall. Most enterprises are not optimistic about the future prices of general-purpose PVDF products. New units that started production during 2014-2015 mostly produce coating-grade products. Like injection/extrusion-grade products, coating-grade products are medium-/low-grade products. Products for high-end applications such as the manufacture of lithium cell binders still have high prices. In mid-2015, prices of domestic coating-grade and injection/extrusion-grade products were around RMB75 000/t, prices of products for high-end applications such as making lithium cell binders were RMB105 000-115 000/t, and prices of imported products were RMB130 000-180 000/t.
Demand for PVDF in the coating sector is biggest, but growth there is quite slow. The membrane material sector is quite sluggish due to the restructuring of related sectors, so its demand for PVDF is limited. The demand for PVDF in making lithium cell binders will be brisk in the future. Domestic products are however mainly for mid-market/low-end applications, and due to technical barriers, high-end PVDF cannot be supplied domestically in great quantities, so demand can hardly be satisfied. In terms of supply, in addition to 29 kt/a of PVDF capacity that already started production during 2014-2015, capacity of nearly 60 kt/a is being constructed or planned for construction (see Table 1). PVDF will continue to be oversupplied in China in the future.

Promising prospect, product upgrading through innovation

PVDF market scale in China is still growing rapidly today. The profit margin has already started to narrow, and market competition is very fierce. Nevertheless, the gross profit margin of high-end products is still quite big, and the market prospects are promising.
With regard to applications, PVDF products produced in China are mainly general-purpose varieties, and most of them are used in making construction coatings. High-end varieties needed in other sectors – photovoltaics, water treatment, lithium cells, electric wire insulation and semiconductor manufacturing equipment – are made domestically only on a very small scale. Only by upgrading and developing products to meet the needs in mid-market/high-end applications can enterprises sell to sectors manufacturing solar cell back membranes, water treatment membranes and high-purity chemicals storage/transport materials. Due to the great regularity and easy crystallization of the PVDF molecular chain, design modification is often made to PVDF molecules. Various modifying monomers are added in polymerization. Typical products include vinylidene fluoride/hexafluoropropylene copolymer used in lithium cells and membranes and vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene terpolymer used to improve the solubility of coatings. It is expected that modified resins will be the major development orientation of the PVDF sector in the future.        

Table 1  PVDF capacity being constructed or planned in China, 2015   (kt/a)

Company    Capacity being constructed or planned     Start of production during 2014-2015
Kureha (Changshu) Fluoropolymers Co., Ltd.    5.0    Production already started
Shandong Dongyue Group Ltd.    5.0    Production already started
Shandong Deyi New Material Co., Ltd.    5.0    Production already started
Jiangsu Sanmei Chemical Co., Ltd.    5.0    Production already started
Longxing Chemical Co., Ltd.    4.0    Production of the first phase already started
Zhejiang Juhua Group Corporation    7.0    Production already started
Others    59.8    -
Total    90.8