What Is a Polyester Coating?
A polyester coating is a coating technique utilizing polyester resin. This type of coating, available in both liquid and powder forms, is known for its thick application achieved through radical polymerization. Polyester coatings are solvent-free, allowing the application of several hundred micrometers thick layers without significant substance volatilization. These coatings are characterized by excellent abrasion, chemical, water, and hot water resistance, along with a glossy finish. However, the thickness can sometimes reduce flexibility and adhesiveness.
Uses of Polyester Coatings
Polyester coatings are frequently used on musical instruments like pianos and guitars due to their high hardness and stain resistance. They are also suitable for outdoor and architectural applications, thanks to their outstanding weather resistance. Common uses include industrial equipment like switchboard boxes, outdoor lighting, signs, aluminum and stainless steel building materials, and electrical appliances such as microwave ovens. However, these coatings are susceptible to strong alkalis, which can cause peeling.
Types of Polyester Coatings
Polyester coatings are broadly classified into liquid and powder types, each with its unique properties and applications:
1. Liquid Type
Liquid polyester coatings use styrene monomer as a diluent instead of conventional solvents like acetone or toluene. Unlike typical solvents, styrene monomer does not volatilize but becomes part of the resin after curing. This property allows for the creation of a thick film without compromising physical properties. Due to its ease of use, liquid polyester coatings are popular among both professional contractors and DIY enthusiasts.
2. Powder Type
Powder polyester coating, or powder coating, involves the use of powdered polyester resin paint. The process starts with electrostatically attaching the powder to the surface, followed by baking to melt and evenly coat the object. This method allows for forming a thick film in a single application. Unused powder can be recovered and reused, making it a cost-effective solution.