Blown oil

A blown oil is a drying oil which has been modified through an oxidative process.

Oils are "blown" through partial oxidation of the oil at elevated temperatures. A typical blowing process involves heating the oil to 70 to 120 °C (158 to 248 °F) and passing air through the liquid. The modification causes the formation of C-O-C and C-C cross links, and hydroxyl and carboxyl functional groups.