Cellulose Nitrate Lacquers

lacquers made from cellulose nitrates, mainly colloxylin. Ketones, esters (acetates), and alcohols, as well as their mixtures with aromatic hydrocarbons (toluene and xylene), are used as solvents in cellulose nitrate lacquers. Aromatic hydrocarbons are used to reduce the cost of the lacquers and in cases where other film-forming materials must be added to improve adhesion and the decorative properties of the films.

Cellulose nitrate lacquers form coatings in 15–30 min at room temperature as a result of evaporation of the solvent. The coatings are soluble (reversible), colorless (colored films are produced from lacquers containing soluble organic dyes), flammable, and resistant to gasoline and mineral oils. They have limited resistance to water and are not resistant to bases, concentrated sulfuric acid, heat, or ultraviolet light. By combining colloxylin with siccative alkyd resins and other film-forming agents, insoluble (nonreversible) films may be produced in 1½ to 3 hr at room temperature. Such films have protective properties superior to those of reversible films.

Cellulose nitrate lacquers are usually applied by pressure or aerosol spraying, as well as by means of a varnish spreader. They are used to produce transparent coatings on wood and metal or for base or finish coats in the application of cellulose nitrate enamels. They are also an intermediate in the production of cellulose nitrate enamels.

In working with cellulose nitrate lacquers, strict observation of fire safety rules is mandatory. Cellulose nitrate lacquers are gradually being replaced by polyacrylic and polyester lacquers and other synthetic film-forming materials.