Published September 2016
Isophthalic acid is an aromatic dicarboxylic acid industrially produced by the oxidation of m-xylene. Commercially it is used primarily as a component of PET (polyethylene terephthalate) copolymer, which is used in bottle resins and, to a much lesser extent, for fibers. Isophthalic acid reduces the crystallinity of PET, which serves to improve clarity and increase the productivity of bottle-making. Isophthalic acid’s second major use is as a component of high-quality alkyds and polyester resins for industrial coatings and unsaturated polyesters for fiberglass-reinforced plastics applications.
The following pie chart shows world consumption of isophthalic acid:
The global market for isophthalic acid is growing at a rate of 4% per year and is driven primarily by increasing production of PET bottle resins and unsaturated polyester resins in China. Other growing markets include the Middle East, CIS countries, Brazil, and the United States, mainly as a result of increasing PET resin production.
In spite of being the major consumer, China is not self-sufficient in isophthalic acid supply, and covers 85% of its domestic demand through imports. Lotte Chemical in South Korea and FCFC in Taiwan are the major exporters of isophthalic acid into China.
In its major applications, PIA competes for use with other materials. In the case of unsaturated polyester resins and polyester surface coating resins, PIA tends to be used only in more demanding applications, as alternative polybasic acids or anhydrides (e.g., phthalic anhydride, terephthalic acid, adipic acid, and trimellitic anhydride) are usually cheaper. In the case of PET copolymer bottle resin, a secondary diol, such as diethylene glycol and/or cyclohexanedimethanol (CHDM), can be added as a partial or full replacement.
The best prospects for growth in consumption of PIA are in developing areas. China will continue to experience steady growth (around 7% per year) in all end-use markets. Demand in Brazil and the Middle East will also see good growth, predominantly as a result of increases in PET bottle resin manufacture. In the Middle East, growing construction activity will also support demand from the surface coating and unsaturated polyester resins market. In Other Asia, traditional applications such as copolyester resin, unsaturated polyester resins, and surface coatings will show only limited growth. The highest growth, although from a small-volume base, is expected in minor applications such as adhesives and aramid fiber.
In North America, consumption of PIA will grow somewhat slowly, driven primarily by increasing PET bottle resin production in the United States. In Europe, consumption growth will be more limited, as PET bottle resin production in the region faces strong competition from material coming from Turkey or in general from the Middle East. Coatings and unsaturated polyester resins will show moderate growth, following limited GDP growth expected for the region.
In Japan, consumption of PIA will continue to decline because of decreasing production of unsaturated polyester resins and continuing lack of growth in housing starts.
At the moment the global market for both isophthalic acid and its m-xylene feedstock is balanced, with ample supply. This situation is expected to persist over the forecast period. The positive growth in demand seems to have created an incentive for new investments, and new capacity for both isophthalic acid and m-xylene has already been planned in Oman, Italy, and Japan.
The global market for isophthalic acid will show positive growth over the next five years. Consumption for PET bottle resin in Asia (particularly in China) and in the Middle East will be the main driver of this growth.