Business Day. Sherwin-Williams, the paint manufacturer, said yesterday that it planned to buy a competitor, Duron, for $253 million to expand its manufacturing capacity.Duron, which is privately held, is a leading paint and wallpaper company in the eastern United States with annual sales of about $350 million.usiness Day. Sherwin-Williams, the paint manufacturer, said yesterday that it planned to buy a competitor, Duron, for $253 million to expand its manufacturing capacity.