Taiwan's Formosa Plastics Corp. plans to shut its acrylonitrile plant at Kaohsiung in February for three weeks for maintenance, a company source said Monday. Formosa Plastics owns a 240,000 mt/year ACN plant, which as of Monday, was running at 80-90% of nameplate capacity. The company also has a 100,000 mt/year acrylic fiber plant, which was running at 50% capacity, 5-10% higher than in December, the source said. The acrylic fiber plant will not be shut while the ACN plant is taken down for maintenance and will rely on existing inventories to maintain production rates. In addition, the company was mulling a hike in production rates at its ACN and acrylic fiber plants with demand for the latter improving, although prices are still low.