The discoloration of furniture paint refers to the change of the appearance color during storage, construction and use, and the color paint fades or changes from one color to another, thus losing the essential color and affecting the aesthetics of the entire home. Everyone knows that furniture paint will change color, so why does furniture paint change color? How can we prevent furniture paint from discoloring?
The discoloration of furniture paint mainly refers to the discoloration of varnish. The varnish is originally transparent and colorless or very pale yellow, and becomes brown or black after discoloration. The color paint also has the phenomenon of discoloration, which is mainly manifested as the darkening of the light color paint.
The reasons for discoloration of furniture paint may be as follows:
1. The ester solvent in the varnish reacts with the iron container and turns black when it comes into contact with water.
2. Turpentine can easily produce reddish-brown pigments in iron drums.
3. Gold and silver powder and varnish are prone to acid etching, which makes the color of the paint green, dark and tarnished.
4. If the storage period is too long, the precipitate will change color.
5. Some pigments in furniture paints will undergo chemical changes, lose their inherent tinting strength, and fade or discolor together. For example, blue or green paints that contain iron will fade during storage, but the paint will gradually recover when exposed to air after application.
6. The light resistance and heat resistance of individual coatings in furniture paints are not good, and some resins have poor weather resistance and are easy to yellow when exposed to light (such as epoxy resin).
7. The densities of several pigments in the multi-color paint are different. During storage, the heavy pigment gradually sinks, and the light pigment gradually floats. If it is not fully stirred during use, it will not match the original color after painting.
The prevention method is:
1. For shellac varnishes, which are most prone to discoloration, use non-metallic containers.
2. Before using the varnish, add gold powder and silver powder. Do not add it to the varnish too early for storage.
3. For precipitation and discolored coatings, if it is not a quality problem, it can be used after thorough stirring.
4. When designing paint formulations, care should be taken not to use pigments that can chemically change with resins or additives. It is strictly forbidden to mix and tint two different types of paints at will without testing during the construction and toning.
5. Resins and pigments in paint formulations are selected as desired. The paint should be fully stirred before application.