Unlike many other types of dyes, disperse dyes are far less water-soluble than other dyes such as acid dyes. As a result, disperse dyes are more commonly used in dye bath solutions. Disperse dyes achieve their best results when the dying process takes place at high temperatures. Specifically, solutions around 120°C to 130°C enable disperse dyes to perform at their optimal levels, enabling the dye to be more evenly distributed and more bold, while at lower temperatures, disperse dyes may result in uneven and less vibrant coloring results. http://www.shengyuchemicals.com/disperse-dyes/