Citigroup Venture Capital International (CVCI) has invested Rs 81 crore in Spentex Industries.According to an official release from Spentex Industries, the board of directors of the company, which met last week, has approved a proposal to issue 1.75 crore equity shares and 17.5 lakh fully convertible warrants to Citigroup.The promoters have also invested in 27.5 lakh equity shares and 2.75 lakh fully convertible warrants, the release added.