Dimer acids, or dimerized fatty acids, are dicarboxylic acids prepared by dimerizing unsaturated fatty acids obtained from tall oil, usually on clay catalysts. The CAS number of the material is [61788-89-4]. Dimer acids are used primarily for synthesis of polyamide resins and polyamide hot melt adhesives. They are also used in alkyd resins, adhesives, surfactants, as fuel oil additives, lubricants, etc. It is a light yellow or yellow viscous transparent liquid.
Dimer acid usually contains predominantly a dimer of oleic acid. It is also called C36 dimer acid.
Trimer acid is a corresponding material where the resulting molecule consists of three fatty acid molecules. Its CAS number is [68937-90-6].
Dimer acids can be converted to dimer amines by reaction with ammonia and subsequent reduction.