lacquer

Lacquer is a broad category of coatings that dry to form a hard, protective film on a surface. It can refer to natural lacquers produced from the sap of certain trees as well as to synthetic coatings formulated from resins and solvents. In both cases, lacquer finishes are typically clear or colored and are valued for their fast drying, gloss, and film strength.

Natural lacquer, also called urushi lacquer, comes from sap of the lacquer tree (for example, Toxicodendron diversilobum in North America or Toxicodendron vernicifluum in Asia). It is applied in thin layers and allowed to cure in open air; each coat hardens through a polymerization process that proceeds with moisture. Traditional urushi finishes can reach very deep gloss and long durability but require careful handling because the sap can irritate skin and eyes. Multiple coats are common, followed by polishing.

Synthetic lacquers are resin- or polymer-based coatings that cure primarily by solvent evaporation. They include nitrocellulose lacquers, acrylic lacquers, polyurethane lacquers, and alkyd lacquers. Compared with natural lacquer, these finishes generally dry faster, are easier to apply in industrial settings, and offer a wide range of colors and clear coats. They can be formulated as solvent-based or water-based systems, and can be tuned for hardness, abrasion resistance, and chemical resistance. Drawbacks include higher VOC content in solvent-based grades and potential solvent shrinkage or cracking in some substrates.

Applications include furniture, musical instruments, automotive and aerospace coatings, metal hardware, and decorative objects. Application methods range from brushing and padding to spraying, with drying times contingent on formulation and environmental conditions. Proper ventilation and personal protective equipment are important due to solvent emissions.