Alkyd coatings are typically sold in three classes: long, medium, and short. These terms represent the relative fraction of drying oil component in the resin.
Long oil alkyds have a high percentage of drying oil content and are generally sold as medium duty coatings for the consumer market.
Medium oil alkyds have less drying oil and have a higher percentage of large molecular weight polyester backbone. They dry slower and are employed as high gloss coatings and wood finishes.
At the bottom end are short oil alkyds where the percentage of drying oil is very low in relation to the base polyester polymer or backbone chain. These coatings will not air dry or harden unless heated. Short oil alkyds are employed as baking enamels for finished metal products, in conjunction with amino /formaldehyde resins.
Key Characteristics of Alkyds:
- Low Cost Consumer Paint
- Available in Many Colors