Gores Group LLC said late Thursday that it led an investor group that has acquired the Cosmopolis specialty cellulose mill in Washington state from Weyerhaeuser Co.

The Los Angeles-based private equity firm did not disclose financial terms of the deal. The mill, which is located southwest of Seattle, was closed by Weyerhaeuser in late 2005. It made a dissolving wood pulp used in viscose and acetate for fabrics; they currently are in tight supply worldwide.

After refurbishment, the facility will reopen under the name Cosmo Specialty Fibers Inc., whose chairman, Dermot Smurfit, is part of the investor group.

“The Cosmopolis mill has a wonderful heritage of producing very high quality products and we are delighted to operate this mill alongside a management team that has substantial experience restarting and managing similar mills,” Jordan W. Katz, a Gores managing director, said in a statement.