Silicone Coatings

Silicone is used for a wide range of products including resins, oil, rubbers and waxes.  In general, silicone coatings are excellent resistors to the suns UV, providing high gloss durability and low weathering. High temperature applications have little effect on the coating properties. Silicone coatings use self-polymerization for its curing system.  They are also water repellent, resistant to corrosion, and have fairly good resistance to other chemicals, however are not as reliable as polyeurathanes and epoxies.

These coatings are produced in many different forms. They can be mixed with a variety of chemicals including polyether, phenyl and methyl. They also come in a variety of forms and compounds such as high solids silicone, water-borne silicone, silicone alkyds, siliconized polyesters, and siliconized acrylics. Each of these combinations provide slightly different characteristics. 

Methyl silicone has a higher resistance to UV and retains its gloss better, while phenyl silicone is more resilient in high-temperature applications, tougher, and provides better protection against corrosion.  When the two chemicals are combined, the silicone coating then provides for more strength and durability.

High-solids and water-borne silicone coatings were introduced to comply with VOC regulations.  Both coatings have little or no solvent addition.  The high-solids coatings have the ability to cure by hydrolisis.  They have low molecular weight and are hard as well as durable against heat.  Water-borne silicone coatings have a higher molecular weight than the high-solids coatings. They have good storage life, and are known to have good life cycles. They can be applied in high temperature application and can prevent corrosion as well.

Another type of coating combines two coatings groups, silicone and alkyd, together.  Silicone alkyds provide very good adhesion to steel, wood, tanks, bridges, and other architectural structures. As with other silicone coatings, they have good life cycles, with properties including durability against chalking and weathering. Similar to the silicone alkyds are the siliconized polyesters.  These coatings provide good rigidity, flexibility and adhesion. Again, they are also resilient to high temperatures. The polyesters are used more on high temperature equipment like coils and cookware.  Siliconized acrylics are also used on high temperature equipment. They have great life expectancy and have a better durability than the polyester silicones. 

Silicone coatings are also used for underwater hull coatings as a anti-fouling coating.  They are also known as foul-release coatings, due to their ability to release organisms from the hull without causing damage to the surrounding environment. These provide a non-toxic, low surface energy coating that is VOC compliant. See Underwater Hull Coatings for more information.