Tri-Chem, Kent, OH, a manufacturer’s representative sales agency marketing pigments and dyes to the plastics, coatings, printing ink and rubber markets, recently established an office in the Knoxville, TN area to cover the southern part of its territory.      Tri-Chem’s Kent office has responsibility for northern Ohio, northern Indiana, eastern Michigan, western Pennsylvania and western New York. Greg Harteis, Matt Harteis and John Frisby work out of this office. The Knoxville office covers s...