1. Air Cured Paints
All paints barring very few are to be mixed with recommended thinners either for brush applications or spray applications. The right viscosity gives the right application and the right optimization of cost. Curing involves open-air drying or oven drying and hardening of paint. Drying enables the evaporation of the mixed solvents and hardening involves hardening of the main polymer base to give a solid appearance. Air-cured paints are available as both slow drying and fast drying.
Acrylic paints are water-based quick drying paints. They constitute organic or inorganic pigments suspended in acrylic polymer emulsion. Post drying acrylic paint becomes water-resistant. The paint film is flexible in the sense that it withstands some amount of warping of the substrate surface. Acrylic paints are generally not meant for large quantity applications but are more suitable for small-sized hand applications.
Nitro Cellulose-based paints are volatile and quick drying. They are mainly used for auto body re paintings, prototypes, and quick-drying works. These types of paints are also available in aerosol cans for ready use.
Enamel paints are air dry-paints well suited for outdoor applications. Enamel paints constitute certain metallic oxides such as zinc, iron, or lead with polyester or epoxy resins used as binders. They are slow-drying paints and gives an opaque and high gloss appearance after drying.
2. Oven Cured Paints
Oven cured paints are industrial paints cured through the heated air that is circulated in the drying ovens. This is generally done by having a heating chamber where the air is heated, and circulated inside the curing oven chambers by means of fans. On the other hand, heating and curing are also done by a series of infrared or ultraviolet lamps arranged inside the ovens.
Polyester based Paints
Polyester paint is a three-component paint that utilizes resins, catalysts, and accelerants. They have a high percentage of solid pigment contents in the paint offering better mechanical and chemical strength.
Polyurethane based Paints
Polyurethane paints are known for their hardness, chemical resistance, and high abrasion resistance. They essentially constitute PolyIsoCynate based polymers. Polyurethanes come in either a mono-component or bi-component product.
Polyester has around 95% solid content, Polyurethane has around 60% solid content. Because polyester has a much higher solid content than polyurethane, polyester’s surface Is stronger. However, polyurethane is more flexible than polyester making it suitable for applications where flexibility is important. Both polyester and polyurethane are UV stabilized.
There are also other methods of painting processes such a vapour cured, and ultraviolet rays cured, though these are not of frequent use.
Vapour cure process makes use of the substrate exposed to vapours generated in a closed chamber to cure the paint coat.
The UV cure process makes use of the substrate exposed to UV lamps for a particular duration to cure the paint.