Process for hydrotreating resins to lighten color

A process for preparing a light colored hydrocarbon resin, said process consisting essentially of (1) polymerizing unsaturated monomers to form a noncrystalline hydrocarbon resin having carbon-carbon double bonds and a weight average molecular weight Mw of 250-10,000, and containing color bodies, and (2) contacting the resin with hydrogen in the absence of polymerization catalyst residues and in the presence of a catalyst that promotes the hydrogenation of the color bodies without substantially changing the softening point or the content of carbon-carbon double bonds in the resin, said resin being selected from the group consisting of C-5 hydrocarbon resins, C-9 hydrocarbon resins, mixed C-5/C-9 hydrocarbon resins, vinyl aromatic-modified C-5 hydrocarbon resins, dicyclopentadiene resins, aromatic-modified dicyclopentadiene resins, terpene resins, and terpene-phenolic resins.