Hybrid coatings based on organic polymers and silicones protect pans, exhaust pipes and wood-burning stoves equally well, and silicone resins add a special degree of heat resistance to such coatings.
250 ºC can be endured for a relatively long period of time by aluminum pans coated with silicone polyester resins. These pans can even withstand 300 °C for a shorter period.
Coated aluminum pans are part of the basic equipment of every kitchen: they are lightweight, inexpensive to produce and accommodate the demands of modern, health-conscious consumers – because aluminum pans require less oil than their expensive cast-iron or stainless-steel counterparts, they make it possible to prepare fish, omelets and pancakes with much less fat. Resistance to heat, however, had long been the Achilles heel of aluminum pans, which is why ambitious chefs prefer other metals for techniques such as frying steaks at high temperatures. Aluminum pans have improved in that regard too, however, as they are usually coated on the inside with polytetrafluoroethylene – known by the brand name Teflon – and on the outside with a finish based on silicone polyester resins.
“Organosilicone resins allow us to adjust the properties of coatings to match the needs of a given application quite closely.”
Marketing Manager at WACKER
Since coated aluminum pans need less oil than their cast-iron or stainless-steel counterparts, they are in line with the trend for healthy, low-fat diets.
“Aluminum pans coated on the outside with silicone polyester resins can remain stable at temperatures of up to 250 °C for relatively long periods of time – even up to 300 °C for short periods,” says Walter Göblmeier, a technical service engineer in the WACKER SILICONES Care & Coatings business team in Burghausen. He added that, in contrast, heat resistance is limited in conventional surface coating resins based on purely organic polymers, but improves markedly when silicones and polyester resins are bound chemically.
Crosslinking takes place during baking, where the applied coating layer, once it has evaporated, is heated to between 250 °C and 280 °C for around 10 to 15 minutes. Used as a binder, the organosilicone resin envelops the solid particles in the coating – pigments and fillers – and binds them together and to the substrate. This forms a strong coating, which protects the treated object against external influences.