Teijin Frontier has unveiled a new version of its Solotex polytrimethylene terephthalate (PTT) fiber, called Solotex Thermo, which is said to offer excellent insulation properties and thermal retention. The fiber absorbs near infrared sunlight and converts it to heat through carbon-based inorganic particles that are mixed into the fiber's monocular structure. A sunlight heat-storage test conducted by the Boken Quality Evaluation Institute showed that compared to conventional polyester fiber, Solotext Thermo raises the wearer's wind-chill factor by 5°C, the company said. According to Teijin, Solotex Thermo is suitable for a wide range of applications, including jeans, pants and bottoms. The company expects the sales of the fiber to reach 500 tons by the fiscal year ending in March 2021.