The private equity firm Platte River Equity has purchased most of Dalton, Ga.-based MFG Chemical. MFG founder and CEO Charles E. Gavin III and MFG management will retain a minority stake in the firm. MFG specializes in chemistry based on maleic anhydride and glacial acrylic acid. From these raw materials the company makes polymers, dioctylsulfosuccinates, and carboxylate esters for oil-field, water treatment, mining, coatings, and agricultural applications. MFG also offers contract manufacturing. It hopes to expand into new chemistries and markets under the new ownership.