Oilmodified

Oilmodified refers to coatings and resins in which a portion of a drying oil has been chemically incorporated into a synthetic resin system, most commonly oil-modified alkyds. This modification aims to combine the film-forming and hardness characteristics of synthetic resins with the flow and leveling properties of drying oils, yielding coatings that cure by oxidation and form a durable film.

Typically produced by reacting a drying oil (such as linseed or soy oil) with polyols and acids to form an alkyd resin, oilmodified formulations are often blended with solvents and additives to control viscosity, drying time, gloss, and film properties. The resulting resins can be used in varnishes, primers, and paints designed for wood and metal, and are frequently marketed as durable, easy-to-apply finishes.

Properties of oilmodified coatings include good adhesion, strong film hardness, and relatively smooth leveling. They usually cure by oxidative crosslinking, offering a balance of durability and workable dry times that are slower than some purely synthetic systems but faster than unmodified drying oils. They may provide decent chemical resistance and UV stability, with gloss levels ranging from satin to high gloss depending on formulation. Limitations can include yellowing of the film in some environments, solvent-based formulations that require proper ventilation, and higher VOC content compared to some waterborne finishes. Compatibility with waterborne coatings varies, and many oilmodified products are designed for traditional solvent cleanup and usage.

Safety considerations include flammability of solvents and the need for adequate ventilation, with standard storage and disposal practices for solvent-based coatings.