How does paint dry chemistry

Phase 1: Evaporation. When the volatile liquids evaporate from the paint film under normal atmospheric conditions. Phase 2: Coalescence. Once the majority of the volatile liquids have evaporated, the process of forming a coherent paint film — from discrete particles of a polymer binder dispersed in the liquids — is known as coalescence.

These ingredients are all necessary to minimise or eliminate undesirable film defects that become visible when the paint is dry. Some additives, such as dispersing agents, anti-settling agents and emulsion stabilizers are also included in the formulation to aid manufacture and stability in the can. Coalescent solvents are also present to promote the final film forming properties of the paint.

The principal aim is to ensure that the coalescent solvents are the last ingredient to leave the paint film. This occurs naturally on warm days with low humidity, above the dew point etc. On high humidity days water pressure from the atmosphere can slow down or stall the release of water from out of the paint film. Just as much water enters the film from the atmosphere as there is water leaving the film. Unfortunately, when this happens, the coalescent solvents may evaporate out of the film before the water does.

Shop Online Find exactly what you need. June 25, No Comments. Leave a Reply Cancel reply Your email address will not be published. Emails are serviced by Constant Contact. Paints are a type of mixture called a colloid. A colloid is a mixture containing tiny particles suspended but not dissolved! Other examples of man made colloids include mayonnaise, body lotion, detergent, and whipped cream.

In the case of paints, the pigment is the tiny particle that is suspended in the solvent-binding medium solution. When paint dries, the solvent portion of the mixture evaporates away, leaving the pigment suspended in the binding medium in a hard layer.

Well, the speed at which the paint dries depends on how much surface area is exposed to the air. When you paint something—for example, a wall—the surface area of the paint increases dramatically relative to the amount of paint present. In freshly applied paint, the particles of pigment and binder are dispersed widely in the liquid.

The film starts to form when the water begins to evaporate. During this process, the particles of pigment and binder come closer together. As the last molecules of liquid evaporate, capillary action draws the binder particles together with great force, causing them to fuse with the pigment into a continuous film.

Love my red garage door and red window trim.