Toray Industries had been originally established as Toyo Rayon in 1926 by Mitsui Bussan, one of the two largest Japanese trading companies of the time . The fact that Mitsui did not allow the company to be named as a Mitsui company indicates their skepticism of the risk on the business. Risk arose from the fact that, when it was established, the company did not have the right technology to produce Rayon. It had approached Courtaulds and then Du Pont to buy the technology but, because the price was too high, it decided to buy equipment from a German engineering company and hire about twenty foreign engineers to start the operation.When Nylon was invented in 1935 by Wallace Carothers of DuPont, Toray immediately got hold of a sample product through the New York City branch of Mitsui Bussan, and started research by dissolving this sample in sulfuric acid. Because of the patent protection, the company had to make its own effort to synthesize polyamide and make fibre out of it. In 1941, just three years after Du Pont's announcement of nylon, Toray completed the basic research on nylon and started building a small plant to produce Nylon 6. The operation started in 1943 and the product was sold, mainly to make fishing nets.
In 1946, following the end of World War II, Du Pont requested an investigation by GHQ of Toray's infringement of Du Pont's nylon patents but GHQ found no evidence of infringement, certifying that Toray's nylon technology was its own.Toray is currently the world's largest producer of carbon fiber, and Japan's largest producer of synthetic fiber. Its carbon fiber is extensively used in exterior components of the Boeing 787 airliner.In 2014, as a major aerospace composites supplier, Toray opened a polyacrylonitrile , the carbon fiber precursor, production line in Lacq, south-western France.
