By Patrick Raleigh UT On-line/news editorWichita, Kansas-Koch Industries, Inc. has completed its $4200-million of Invista, from DuPont. The purchase includes the assumption of debt and certain joint venture and equity interests covered under a non-binding letter of intent, said a 30 April joint statement. Going forward, the company will conduct business as Invista, according to Koch."Our focus for the near future is to enhance this business' ability to create superior value for our global customers," said Jeff Walker, Invista's chief executive officer. "We believe that this combination of Invista's strengths, primarily in nylon and spandex, and KoSa's polyester capabilities will position us to compete successfully in the global resins and fibres markets," he added.Invista is a world leader in the supply of polyurethane-based spandex fibre as well as of nylon fibre. Koch is a global producer of commodity and speciality polyester fibres, polymers and intermediates, via its Kosa Inc. subsidiary. Wichita-based was previously represented in the PU sector through its KoSa subsidiary, which is one of the world's largest makers of aromatic polyester polyols for rigid PU foam applications. Invista is the world's largest producer of spandex business-elastomeric polyurethane fibre produced by reacting polytetramethylene ether glycol (PTMEG) with isocyanates. The company's Lycra-branded fibre claims around 40 percent of the 250-kilotonne global market for spandex.Invista is also the world's largest producer of adipic acid with up to 47 percent of the global market. While adipic acid is mainly used as a nylon feedstock, around 10 percent is used in the production of polyester polyols, which are used in turn to make PU foams, elastomers and footwear components. Further downstream, Invista is actively developing applications for Lycra-based compounds in film-based technologies such as gloves, condoms, and synthetic leather. Koch is the second largest privately owned company in North America, with 2002 sales of around $40 000 million, according to Forbes. The firm purchased KoSa from Hoechst in two separate deals between 1998 and 2001.Koch defines itself as "a diverse group of companies" operating globally in industries such as finance, petroleum, asphalt, natural gas, chemicals, plastics and fibres, chemical technology equipment, minerals and fertilisers. "